US20130160831A1 - Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer - Google Patents
Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer Download PDFInfo
- Publication number
- US20130160831A1 US20130160831A1 US13/334,296 US201113334296A US2013160831A1 US 20130160831 A1 US20130160831 A1 US 20130160831A1 US 201113334296 A US201113334296 A US 201113334296A US 2013160831 A1 US2013160831 A1 US 2013160831A1
- Authority
- US
- United States
- Prior art keywords
- layer
- iii
- semiconductor layer
- type
- depositing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000005546 reactive sputtering Methods 0.000 title claims abstract description 35
- 229910052739 hydrogen Inorganic materials 0.000 title claims description 15
- 239000004065 semiconductor Substances 0.000 claims abstract description 185
- 238000000151 deposition Methods 0.000 claims abstract description 86
- 239000006096 absorbing agent Substances 0.000 claims abstract description 84
- 238000000034 method Methods 0.000 claims abstract description 62
- 239000000758 substrate Substances 0.000 claims abstract description 52
- KTSFMFGEAAANTF-UHFFFAOYSA-N [Cu].[Se].[Se].[In] Chemical compound [Cu].[Se].[Se].[In] KTSFMFGEAAANTF-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000000956 alloy Substances 0.000 claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 claims abstract description 10
- 229910052723 transition metal Inorganic materials 0.000 claims description 104
- 150000003624 transition metals Chemical class 0.000 claims description 104
- 239000011701 zinc Substances 0.000 claims description 74
- 238000004544 sputter deposition Methods 0.000 claims description 71
- 239000003513 alkali Substances 0.000 claims description 57
- 239000011734 sodium Substances 0.000 claims description 57
- 229910052708 sodium Inorganic materials 0.000 claims description 41
- 238000009792 diffusion process Methods 0.000 claims description 38
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 37
- 229910052725 zinc Inorganic materials 0.000 claims description 32
- 229910052750 molybdenum Inorganic materials 0.000 claims description 24
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 21
- 239000002184 metal Substances 0.000 claims description 21
- 239000011733 molybdenum Substances 0.000 claims description 21
- 229910052711 selenium Inorganic materials 0.000 claims description 21
- 229910052717 sulfur Inorganic materials 0.000 claims description 21
- 229910052984 zinc sulfide Inorganic materials 0.000 claims description 19
- 229910021476 group 6 element Inorganic materials 0.000 claims description 16
- 229910052738 indium Inorganic materials 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 15
- 238000000137 annealing Methods 0.000 claims description 14
- 239000007789 gas Substances 0.000 claims description 14
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 12
- 239000011593 sulfur Substances 0.000 claims description 12
- 239000001257 hydrogen Substances 0.000 claims description 8
- 238000012544 monitoring process Methods 0.000 claims description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 7
- SBIBMFFZSBJNJF-UHFFFAOYSA-N selenium;zinc Chemical compound [Se]=[Zn] SBIBMFFZSBJNJF-UHFFFAOYSA-N 0.000 claims description 7
- 239000005083 Zinc sulfide Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 6
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 5
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 229910052700 potassium Inorganic materials 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- 238000001637 plasma atomic emission spectroscopy Methods 0.000 claims description 4
- 230000007812 deficiency Effects 0.000 claims description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- 150000001340 alkali metals Chemical class 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 330
- 229910052760 oxygen Inorganic materials 0.000 description 32
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 30
- 230000004888 barrier function Effects 0.000 description 30
- 239000000463 material Substances 0.000 description 30
- 239000001301 oxygen Substances 0.000 description 30
- 239000011669 selenium Substances 0.000 description 28
- 150000001875 compounds Chemical class 0.000 description 23
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 14
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 11
- 229940091258 selenium supplement Drugs 0.000 description 11
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 10
- 238000005477 sputtering target Methods 0.000 description 10
- 125000004429 atom Chemical group 0.000 description 9
- 239000010949 copper Substances 0.000 description 8
- 230000008021 deposition Effects 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 7
- 229910052733 gallium Inorganic materials 0.000 description 7
- 239000012535 impurity Substances 0.000 description 7
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 5
- 238000001755 magnetron sputter deposition Methods 0.000 description 5
- 238000001552 radio frequency sputter deposition Methods 0.000 description 5
- 239000011775 sodium fluoride Substances 0.000 description 5
- 235000013024 sodium fluoride Nutrition 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 230000002950 deficient Effects 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- -1 molybdenum Chemical class 0.000 description 4
- 239000010955 niobium Substances 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 229910052793 cadmium Inorganic materials 0.000 description 3
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- HVMJUDPAXRRVQO-UHFFFAOYSA-N copper indium Chemical compound [Cu].[In] HVMJUDPAXRRVQO-UHFFFAOYSA-N 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 239000011684 sodium molybdate Substances 0.000 description 3
- 235000015393 sodium molybdate Nutrition 0.000 description 3
- TVXXNOYZHKPKGW-UHFFFAOYSA-N sodium molybdate (anhydrous) Chemical compound [Na+].[Na+].[O-][Mo]([O-])(=O)=O TVXXNOYZHKPKGW-UHFFFAOYSA-N 0.000 description 3
- VPQBLCVGUWPDHV-UHFFFAOYSA-N sodium selenide Chemical compound [Na+].[Na+].[Se-2] VPQBLCVGUWPDHV-UHFFFAOYSA-N 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- PFNQVRZLDWYSCW-UHFFFAOYSA-N (fluoren-9-ylideneamino) n-naphthalen-1-ylcarbamate Chemical compound C12=CC=CC=C2C2=CC=CC=C2C1=NOC(=O)NC1=CC=CC2=CC=CC=C12 PFNQVRZLDWYSCW-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910002056 binary alloy Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- ZZEMEJKDTZOXOI-UHFFFAOYSA-N digallium;selenium(2-) Chemical compound [Ga+3].[Ga+3].[Se-2].[Se-2].[Se-2] ZZEMEJKDTZOXOI-UHFFFAOYSA-N 0.000 description 2
- QXYJCZRRLLQGCR-UHFFFAOYSA-N dioxomolybdenum Chemical compound O=[Mo]=O QXYJCZRRLLQGCR-UHFFFAOYSA-N 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 2
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- SPVXKVOXSXTJOY-UHFFFAOYSA-N selane Chemical compound [SeH2] SPVXKVOXSXTJOY-UHFFFAOYSA-N 0.000 description 2
- 229910000058 selane Inorganic materials 0.000 description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- 229910001948 sodium oxide Inorganic materials 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- PMYDPQQPEAYXKD-UHFFFAOYSA-N 3-hydroxy-n-naphthalen-2-ylnaphthalene-2-carboxamide Chemical compound C1=CC=CC2=CC(NC(=O)C3=CC4=CC=CC=C4C=C3O)=CC=C21 PMYDPQQPEAYXKD-UHFFFAOYSA-N 0.000 description 1
- 229910004613 CdTe Inorganic materials 0.000 description 1
- 229910017612 Cu(In,Ga)Se2 Inorganic materials 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- 206010022004 Influenza like illness Diseases 0.000 description 1
- 208000019693 Lung disease Diseases 0.000 description 1
- 208000000112 Myalgia Diseases 0.000 description 1
- 229910000528 Na alloy Inorganic materials 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 206010037660 Pyrexia Diseases 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910004166 TaN Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 229910008322 ZrN Inorganic materials 0.000 description 1
- UEEBPQBGLVAFMF-UHFFFAOYSA-M [Al+3].[Se-2].[SeH-] Chemical compound [Al+3].[Se-2].[SeH-] UEEBPQBGLVAFMF-UHFFFAOYSA-M 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- KNYGDGOJGQXAMH-UHFFFAOYSA-N aluminum copper indium(3+) selenium(2-) Chemical compound [Al+3].[Cu++].[Se--].[Se--].[In+3] KNYGDGOJGQXAMH-UHFFFAOYSA-N 0.000 description 1
- WGMIDHKXVYYZKG-UHFFFAOYSA-N aluminum copper indium(3+) selenium(2-) Chemical compound [Al+3].[Cu++].[Se--].[Se--].[Se--].[Se--].[In+3] WGMIDHKXVYYZKG-UHFFFAOYSA-N 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- FQNHWXHRAUXLFU-UHFFFAOYSA-N carbon monoxide;tungsten Chemical group [W].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-] FQNHWXHRAUXLFU-UHFFFAOYSA-N 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- DVRDHUBQLOKMHZ-UHFFFAOYSA-N chalcopyrite Chemical compound [S-2].[S-2].[Fe+2].[Cu+2] DVRDHUBQLOKMHZ-UHFFFAOYSA-N 0.000 description 1
- 229910052951 chalcopyrite Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000001684 chronic effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- JAONJTDQXUSBGG-UHFFFAOYSA-N dialuminum;dizinc;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Al+3].[Al+3].[Zn+2].[Zn+2] JAONJTDQXUSBGG-UHFFFAOYSA-N 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 208000028659 discharge Diseases 0.000 description 1
- BVTBRVFYZUCAKH-UHFFFAOYSA-L disodium selenite Chemical compound [Na+].[Na+].[O-][Se]([O-])=O BVTBRVFYZUCAKH-UHFFFAOYSA-L 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 210000003734 kidney Anatomy 0.000 description 1
- 208000017169 kidney disease Diseases 0.000 description 1
- 201000006370 kidney failure Diseases 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 231100001231 less toxic Toxicity 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 150000003346 selenoethers Chemical class 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- GROMGGTZECPEKN-UHFFFAOYSA-N sodium metatitanate Chemical compound [Na+].[Na+].[O-][Ti](=O)O[Ti](=O)O[Ti]([O-])=O GROMGGTZECPEKN-UHFFFAOYSA-N 0.000 description 1
- CMZUMMUJMWNLFH-UHFFFAOYSA-N sodium metavanadate Chemical compound [Na+].[O-][V](=O)=O CMZUMMUJMWNLFH-UHFFFAOYSA-N 0.000 description 1
- 239000011655 sodium selenate Substances 0.000 description 1
- 235000018716 sodium selenate Nutrition 0.000 description 1
- 229960001881 sodium selenate Drugs 0.000 description 1
- 229960001471 sodium selenite Drugs 0.000 description 1
- 239000011781 sodium selenite Substances 0.000 description 1
- 235000015921 sodium selenite Nutrition 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- 229940079101 sodium sulfide Drugs 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 229940001482 sodium sulfite Drugs 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- XMVONEAAOPAGAO-UHFFFAOYSA-N sodium tungstate Chemical compound [Na+].[Na+].[O-][W]([O-])(=O)=O XMVONEAAOPAGAO-UHFFFAOYSA-N 0.000 description 1
- 238000005478 sputtering type Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- IHIXIJGXTJIKRB-UHFFFAOYSA-N trisodium vanadate Chemical compound [Na+].[Na+].[Na+].[O-][V]([O-])([O-])=O IHIXIJGXTJIKRB-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
- H01L31/0264—Inorganic materials
- H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
- H01L31/0322—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/541—CuInSe2 material PV cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates generally to the field of photovoltaic devices, and more specifically to CIGS thin-film solar cells comprising alkali and zinc doping.
- gallium usually replaces 20% to 30% of the normal indium content to raise the band gap; however, there are significant and useful variations outside of this range. If gallium is replaced by aluminum, smaller amounts of aluminum are used to achieve the same band gap.
- One embodiment of this invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode.
- the p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material.
- the method also includes depositing by reactive sputtering an n-type In-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing a second electrode over the n-type In-VI semiconductor layer.
- Another embodiment of the invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode.
- the p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material.
- the method also includes depositing by reactive sputtering a first (II,III)-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing by reactive sputtering a second (II,III)-VI semiconductor layer over the first (II,III)-VI semiconductor layer, wherein a ratio of Group VI element to at least one of Group II or Group III elements in the first (II,III)-VI semiconductor layer is smaller than the ratio of Group VI element to at least one of Group II or Group III elements in the second (II,III)-VI semiconductor layer.
- Another embodiment of the invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode.
- the p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material.
- the method also includes depositing by reactive sputtering an n-type II-III-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing a second electrode of the n-type semiconductor layer.
- a solar cell including a substrate, a first electrode over the substrate and at least one p-type semiconductor absorber layer over the first electrode, wherein the p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material.
- the solar cell also includes a first sodium doped n-type (II,III)-VI semiconductor layer on the at least one p-type semiconductor absorber layer, a second n-type (II,III)-VI semiconductor layer over the first n-type (II,III)-VI semiconductor layer and a second electrode over the a second n-type (II,III)-VI semiconductor layer.
- FIG. 1 is a schematic side cross-sectional view of a CIS based solar cell according to one embodiment of the invention.
- FIG. 2 shows a highly simplified schematic diagram of a top view of a sputtering apparatus that can be used to forming a first transition metal layer such as an alkali-containing transition metal layer, for example, a sodium-containing molybdenum film.
- a first transition metal layer such as an alkali-containing transition metal layer, for example, a sodium-containing molybdenum film.
- FIG. 3A shows a highly simplified schematic diagram of a top view of a modular sputtering apparatus that can be used to manufacture the solar cell depicted in FIG. 1 .
- FIG. 3 B illustrates schematically the use of three sets of dual magnetrons to increase the deposition rate and grade the composition of the CIS layer to vary its band gap.
- FIGS. 4A and 4B are schematic side cross-sectional views of an in-process CIS based solar cell according to another embodiment of the invention.
- FIGS. 5A and 5B are schematic side cross-sectional views of an in-process CIS based solar cell according to another embodiment of the invention.
- CIS or CIGS solar cells include a CdS buffer layer between the CIS or CIGS absorber layer and the top transparent conductive oxide electrode.
- CdS buffer layer between the CIS or CIGS absorber layer and the top transparent conductive oxide electrode.
- cadmium is a highly toxic material. Long term or chronic exposure, such as in the workplace, has been linked to kidney and lung disorders. Even short term exposure may lead to flu-like symptoms, such as fever, chills, muscle aches. Thus, it would be advantageous to replace the CdS buffer layer with a layer comprising less toxic materials.
- One embodiment of this invention provides a solar cell comprising a substrate, a first electrode located over the substrate, where the first electrode comprises a first transition metal layer, at least one p-type semiconductor absorber layer located over the first electrode, an n-type In-VI semiconductor layer located over the p-type semiconductor absorber layer, and a second electrode located over the n-type semiconductor layer.
- a solar cell contains a substrate 100 and a first (lower) electrode 200 .
- the first electrode 200 comprises a first transition metal layer 202 that contains (i) an alkali element or an alkali compound and (ii) a lattice distortion element or a lattice distortion compound.
- the first transition metal layer 202 contains an alkali element or an alkali compound but substantially free of the lattice distortion element or compound.
- the transition metal of the first transition metal layer 202 may be any suitable transition metal, for example but not limited to Mo, W, Ta, V, Ti, Nb, and Zr.
- the alkali element or alkali compound may comprise one or more of Li, Na, and K.
- the lattice distortion element or the lattice distortion compound may be any suitable element or compound, for example, oxygen, nitrogen, sulfur, selenium, an oxide, a nitride, a sulfide, a selenide, an organometallic compound (e.g. a metallocene, a metal carbonyl such as tungsten pentacyonyl and tungsten hexacarbonyl, and the like), or a combination thereof.
- the first transition metal layer 202 may comprise at least 59 atomic percent molybdenum, 5 to 40 atomic percent oxygen such as around 20 atomic percent oxygen, and 0.01 to 1.5 atomic percent sodium. In some embodiments, the first transition metal layer 202 may comprise 10 21 to 10 23 atoms/cm 3 sodium.
- the first transition metal layer 202 may have a thickness of 100 to 500 nm, for example 200 to 400 nm such as around 300 nm.
- the first transition metal layer 202 may comprise multiple sub-layers, for example 1 to 20 sub-layers such as 1 to 10 sub-layers. Each sub-layer has a different sodium concentration, resulting in a graded sodium concentration profile within the first transition metal layer 202 .
- the lattice distortion element or the lattice distortion compound has a crystal structure different from that of the first transition metal layer to distort a polycrystalline lattice of the first transition metal layer 202 .
- the lattice distortion element when the transition metal is molybdenum, the lattice distortion element may be oxygen, forming the first transition metal layer 202 of body centered cubic Mo lattice distorted by face centered cubic oxide compositions, such as MoO 2 and MoO 3 .
- the density of the first transition metal layer 202 may be reduced due to a greater interplanar spacing as a result of the lattice distortion.
- the lattice distortion element may exist as substitutional or interstitial atoms, rather than forming a compound with other impurities or the matrix of the first transition metal layer 202 .
- the first electrode 200 of the solar cell may comprise an alkali diffusion barrier layer 201 located between the substrate 100 and the first transition metal layer 202 , and/or a second transition metal layer 203 located over the first transition metal layer 202 .
- Additional adhesion layer (not shown) may be further disposed between the electrode 200 and the substrate 100 , for example between the optional alkali diffusion barrier layer 201 and the substrate 100 .
- the optional alkali diffusion barrier layer 201 and second transition metal layer 203 may comprise any suitable materials.
- they may be independently selected from a group consisting Mo, W, Ta, V, Ti, Nb, Zr, Cr, TiN, ZrN, TaN, VN, or combinations thereof.
- the first transition metal layer 202 and/or the second transition metal layer 203 may contain oxygen and/or be deposited at a higher pressure than the alkali diffusion barrier layer 201 to achieve a lower density than the alkali diffusion barrier layer 201 .
- other impurity elements e.g. lattice distortion elements or the lattice distortion compounds described above, instead of or in addition to oxygen, may be contained in the second transition metal layer 202 and/or the second transition metal layer 203 to reduce the density thereof.
- the alkali diffusion barrier layer 201 may be in compressive stress and have a thickness greater than that of the second transition metal layer 203 .
- the alkali diffusion barrier layer 201 may have a thickness of around 100 to 400 nm such as 100 to 200 nm, while the second transition metal layer 203 has a thickness of around 50 to 200 nm such as 50 to 100 nm.
- layer 201 may comprise molybdenum, in alternative embodiments it may comprise other materials, such as TiN or other barrier materials listed above.
- the higher density and greater thickness of the alkali diffusion barrier layer 201 substantially reduces/prevents alkali diffusion from the first transition metal layer 202 into the substrate 100 .
- the second transition metal layer 203 has a higher porosity than the alkali diffusion barrier layer 201 and permits alkali diffusion from the first transition metal layer 202 into the p-type semiconductor absorber layer 301 .
- alkali may diffuse from the first transition metal layer 202 , through the lower density second transition metal layer 203 , into the at least one p-type semiconductor absorber layer 301 during and/or after the step of depositing the at least one p-type semiconductor absorber layer 301 .
- the optional alkali diffusion barrier layer 201 and/or optional second transition metal layer 203 may be omitted.
- the optional second transition metal layer 203 is omitted, the at least one p-type semiconductor absorber layer 301 is deposited over the first transition metal layer 202 , and alkali may diffuse from the first transition metal layer 202 into the at least one p-type semiconductor absorber layer 301 during or after the deposition of the at least one p-type semiconductor absorber layer 301 .
- the p-type semiconductor absorber layer 301 may comprise a CIS based alloy material selected from copper indium selenide, copper indium gallium selenide, copper indium aluminum selenide, or combinations thereof.
- Layer 301 may have a stoichiometric composition having a Group I to Group III to Group VI atomic ratio of about 1:1:2, or a non-stoichiometric composition having an atomic ratio of other than about 1:1:2.
- layer 301 is slightly copper deficient and has a slightly less than one copper atom for each one of Group III atom and each two of Group VI atoms.
- the step of depositing the at least one p-type semiconductor absorber layer 301 may comprise reactively AC sputtering the semiconductor absorber layer from at least two electrically conductive targets in a sputtering atmosphere that comprises argon gas and a selenium containing gas (e.g. selenium vapor or hydrogen selenide).
- a sputtering atmosphere that comprises argon gas and a selenium containing gas (e.g. selenium vapor or hydrogen selenide).
- each of the at least two electrically conductive targets comprises copper, indium and gallium; and the CIS based alloy material comprises copper indium gallium diselenide.
- the p-type semiconductor absorber layer 301 may comprise 0.03 to 1.5 atomic percent sodium diffused from the first transition metal layer 202 .
- sodium impurities may diffuse from the first transition metal layer 202 to the CIS based alloy layer 301 .
- the sodium impurities may concentrate at the grain boundaries of CIS based alloy, and may have a concentration
- an n-type semiconductor layer 302 may then be deposited over the p-type semiconductor absorber layer 301 .
- one or more layers are deposited on the absorber layer 301 and then annealed to form the n-type semiconductor layer.
- the n-type semiconductor layer 302 may comprise any suitable n-type semiconductor materials.
- Suitable materials for the n-type semiconductor layer 302 include but are not limited to In-VI semiconductors, such as In 2 Se 3 , In 2 S 3 , In 2 (Se 1 ⁇ x S x ) 3 , (In 2 ⁇ y Zn 1 ⁇ y )Se 4 , (In 2 ⁇ y Zn 1 ⁇ y )S 4 or (In 2 ⁇ y Zn 1 ⁇ y )(Se 1 ⁇ x S x ) 4 , where 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1 and (In x Zn 1 ⁇ x ) 2+z (Se y S 1 ⁇ y ) 3+z , wherein 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, and 0 ⁇ z ⁇ 1.
- In-VI semiconductors such as In 2 Se 3 , In 2 S 3 , In 2 (Se 1 ⁇ x S x ) 3 , (In 2 ⁇ y Zn 1 ⁇ y )Se 4 , (In 2 ⁇ y Zn 1 ⁇ y )S 4 or (In 2 ⁇ y Zn
- suitable semiconductor materials include (II,III)-VI semiconductors, such as semiconductor materials which include at least one of Zn and In, and at least one of S and Se, such as ZnSe:Na and Zn(Se y S 1 ⁇ y ):Na, wherein 0 ⁇ y ⁇ 1.
- (II,III)-VI semiconductor includes semiconductors which include: a) a Group VIA element (e.g., S and/or Se), and b) either a Group IIB element (e.g., Zn) or a Group IIIA element (e.g., In) or both a Group IIB and a Group IIIA element (e.g., both Zn and In).
- the VI semiconductor excludes cadmium other than unavoidable Cd impurity.
- the term “II-III-VI semiconductor” includes semiconductors which include: a) a Group VIA element (e.g., S and/or Se), and b) a Group IIB element (e.g., Zn), and c) a Group IIIA element (e.g., In).
- a second electrode 400 is further deposited over the n-type semiconductor layer 302 .
- the transparent top electrode 400 may comprise multiple transparent conductive layers, for example, but not limited to, an Indium Tin Oxide (ITO) layer 402 located over an optional intrinsic Zinc Oxide or a resistive Aluminum Zinc Oxide (AZO, also referred to as RAZO) layer 401 .
- ITO Indium Tin Oxide
- AZO resistive Aluminum Zinc Oxide
- the transparent top electrode 400 may comprise any other suitable materials, for example, doped ZnO or SnO.
- one or more antireflection (AR) films may be deposited over the transparent top electrode 400 , to optimize the light absorption in the cell, and/or current collection grid lines may be deposited over the top conducting oxide.
- AR antireflection
- the solar cell may be formed in reverse order.
- a transparent electrode is deposited over a substrate, followed by depositing an n-type semiconductor layer over the transparent electrode, depositing at least one p-type semiconductor absorber layer over the n-type semiconductor layer, depositing a first transition metal layer over the at least one p-type semiconductor absorber layer, and optionally depositing a second transition metal layer between the first transition metal layer and the p-type semiconductor absorber layer and/or depositing a alkali diffusion barrier layer 201 over the first transition metal layer 202 .
- the substrate may be a transparent substrate (e.g., glass) or opaque (e.g., metal). If the substrate used is opaque, then the initial substrate may be delaminated after the steps of depositing the stack of the above described layers, and then bonding a glass or other transparent substrate to the transparent electrode of the stack.
- a solar cell described above may be fabricated by any suitable methods.
- a method of manufacturing such a solar cell comprising providing a substrate 100 , depositing a first electrode 200 over the substrate 100 , depositing at least one p-type semiconductor absorber layer 301 over the first electrode 200 , depositing an n-type semiconductor layer 302 over the p-type semiconductor absorber layer 301 , and depositing a second electrode 400 over the n-type semiconductor layer 302 .
- the step of depositing the first electrode 200 comprises depositing the first transition metal layer 202 . While sputtering was described as the preferred method for depositing all layers onto the substrate, some layers may be deposited by MBE, CVD, evaporation, plating, etc. In some embodiments, one or more sputtering steps may be reactive sputtering.
- the lattice distortion element or compound may be contained in at least one of the sputtering target used for sputtering the first transition metal layer 202 .
- the step of sputtering the first transition metal layer 202 comprises sputtering from a target comprising a combination of the transition metal, the alkali element/compound, and the lattice distortion element/compound, for example, a sodium molybdate target.
- the target may comprise 5 to 40 atomic percent oxygen, such as around 20 atomic percent oxygen, 0.01 to 1.5 atomic percent sodium, and balance molybdenum.
- the step of sputtering the first transition metal layer 202 comprises sputtering from at least one pair of sputtering targets having different compositions from each other.
- the at least one pair of sputtering targets are selected from: (i) a first molybdenum target and a second sodium molybdate or sodium oxide target; (ii) a first molybdenum oxide target (e.g., a molybdenum target containing 5 to 40 atomic percent oxygen, such as around 20 atomic percent oxygen) and a second sodium selenide, sodium fluoride, sodium selenide or sodium sulfate target; or (iii) a first molybdenum target and a second sodium target in an oxygen containing reactive sputtering system.
- the at least one pair of targets is located in the same vacuum chamber of a magnetron sputtering system.
- reactive sputtering may be used to introduce the lattice distortion element or compound, such as oxygen, nitrogen, etc., from a gas phase instead of or in addition to from a sputtering target.
- a target comprising both transition metal and alkali element/compound, or a pair of target comprising one transition metal target (e.g. a Mo target) and one alkali element/compound target (e.g. a NaF target) may be used.
- the transition metal target may be substantially free of alkali.
- the term “substantially free of alkali” means that no alkali metal or other alkali-containing material is intentionally alloyed or doped, but unavoidable impurities of alkali may present. If desired, more than two targets may be used to sputter the first transition metal layer 202 .
- the first transition metal layer (not shown in FIG. 2 , and referred to as layer 202 in FIGS. 1 ) may be deposited over a substrate 100 .
- Targets comprising an alkali-containing material e.g., targets 37 a and 37 b
- targets comprising a transition metal e.g., 27 a and 27 b
- a sputtering process module 22 a such as a vacuum chamber.
- the transition metal targets 27 a and 27 b are rotating Mo cylinders and are powered by DC power sources 7
- the alkali-containing targets 37 a and 37 b are planar NaF targets and are powered by RF generators 6 through matching networks 5 .
- the target types alternate and end with a transition metal target, for example target 27 b as shown in FIG. 2 .
- the distance between the adjacent targets is small enough such that a sufficient overlap 9 may exist between the alternating transition and metal alkali containing fluxes and thus enhance the intermixing of the transition metal and the alkali-containing material during depositing the alkali-containing transition metal layer.
- the step of depositing the first transition metal layer 202 may be conducted in an oxygen and/or nitrogen rich environment, and may comprise DC sputtering the transition metal from the first target and pulsed DC sputtering, AC sputtering, or RF sputtering the alkali compound from the second target. Any suitable variations of the sputtering methods may be used.
- AC sputtering refers to any variation of AC sputtering methods that may be used to for insulating target sputtering, such as medium frequency AC sputtering or AC pairs sputtering.
- the step of depositing the first transition metal layer may comprise DC sputtering a first target comprising a transition metal, such as molybdenum, and pulsed DC sputtering, AC sputtering, or RF sputtering a second target comprising alkali-containing material, such as a sodium-containing material, in an oxygen rich sputtering environment.
- a transition metal such as molybdenum
- RF sputtering a second target comprising alkali-containing material such as a sodium-containing material
- the substrate 100 may be a foil web, for example, a metal web substrate, a polymer web substrate, or a polymer coated metal web substrate, and may be continuously passing through the sputtering module 22 a during the sputtering process, following the direction of the imaginary arrow along the web 100 .
- Any suitable materials may be used for the foil web.
- metal e.g., stainless steel, aluminum, or titanium
- thermally stable polymers e.g., polyimide or the like
- the foil web 100 may move at a constant or variable rate to enhance intermixing.
- the sodium-containing material may comprise any material containing sodium, for example alloys or compounds of sodium with one or more of selenium, sulfur, oxygen, nitrogen or barrier metal (such as molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium), such as sodium fluoride, sodium molybdate, sodium fluoride, sodium selenide, sodium hydroxide, sodium oxide, sodium sulfate, sodium tungstate, sodium selenate, sodium selenite, sodium sulfide, sodium sulfite, sodium titanate, sodium metavanadate, sodium orthovanadate, or combinations thereof.
- barrier metal such as molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium
- barrier metal such as molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium
- barrier metal such as molybdenum, tungsten, tantalum, van
- Alloys or compounds of lithium and/or potassium may be also used, for example but not limited to alloys or compounds of lithium or potassium with one or more of selenium, sulfur, oxygen, nitrogen, molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium.
- the transition metal target may comprise a pure metal target, a metal alloy target, a metal oxide target (such as a molybdenum oxide target), etc.
- the transition metal is molybdenum
- the first transition metal layer 202 comprises molybdenum intentionally doped with oxygen and at least one alkali element, such as sodium.
- the oxygen can be omitted or replaced with any lattice distortion elements.
- sodium may be replaced in whole or in part by lithium or potassium.
- the first transition layer 202 may contain elements other than molybdenum, oxygen and sodium, such as other materials that are diffused into this layer during deposition, such as indium, copper, selenium and/or barrier layer metals.
- the amount of sodium diffused into the at least one p-type semiconductor absorber layer 301 may be tuned by independently controlling the thickness of deposited molybdenum sublayers and the thickness of sodium-containing sublayers in the first transition layer, by independently tuning the sputtering rate of the first target comprising molybdenum and the sputtering rate of the second target comprising sodium.
- a variable sodium content as a function of thickness in the sodium-containing molybdenum layer may also be generated by independently controlling the thickness of the deposited molybdenum sublayers and the thickness of the sodium-containing sublayers in the first transition metal layer 202 .
- the molybdenum sublayers and the sodium-containing sublayers may become intermixed, forming a continuous sodium-containing molybdenum layer, during at least one of the steps of depositing the first transition metal layer 202 , depositing the at least one p-type semiconductor absorber layer 301 , or an optional post-deposition annealing process.
- the step of depositing the first electrode 200 further comprises depositing an alkali diffusion barrier layer 201 between the substrate 100 and the first transition metal layer 202 , and depositing a second transition metal layer 203 over the first transition metal layer 202 .
- the step of sputtering the alkali diffusion barrier layer 201 occurs at a lower pressure than the step of sputtering the second transition metal layer 203 .
- the step of sputtering the alkali diffusion barrier layer 201 occurs under a first sputtering environment in a first vacuum chamber of a magnetron sputtering system, while the step of sputtering the second transition metal layer 203 occurs under a second sputtering environment in a second vacuum chamber of the magnetron sputtering system different from the first vacuum chamber.
- the second sputtering environment differs from the first sputtering environment in at least one of argon pressure, oxygen pressure, or nitrogen pressure.
- the step of sputtering the alkali diffusion barrier layer 201 may occur in an oxygen free atmosphere, while the step of sputtering the second transition metal layer 203 occurs in an oxygen containing atmosphere.
- the step of depositing the alkali diffusion barrier layer 201 may comprise sputtering from a metal target under 0.8 to 1.2 mtorr such as around 1 mtorr in an inert environment, while the step of depositing the second transition metal layer 203 comprises sputtering from an transition metal target under 2 to 8 mtorr in an oxygen and/or nitrogen rich environment.
- the sputtering power used for depositing the alkali diffusion barrier layer 201 and depositing the second transition metal layer 203 may also be different.
- the sputtering power used for depositing the alkali diffusion barrier layer 201 may be higher than that used for depositing the second transition metal layer 203 .
- the step of sputtering the first transition metal layer 202 may occur in the first or the second vacuum chamber.
- a first transition metal layer 202 containing lattice distortion element/compound(s) may be deposited in the second vacuum chamber in which the second transition metal layer 203 is deposited.
- the first transition metal layer 202 may be deposited in the first vacuum chamber in which the alkali diffusion barrier layer 201 is deposited.
- the step of sputtering the first transition metal layer 202 may occur in a third vacuum chamber of the magnetron sputtering system different from the first and the second vacuum chambers.
- the step of depositing the first electrode 200 comprises sputtering the alkali diffusion barrier layer 201 , sputtering the first transition metal layer 202 , and sputtering the second transition metal layer 203 in the same sputtering apparatus.
- the steps of depositing the first electrode 200 , depositing the at least one p-type semiconductor absorber layer 301 , depositing the n-type semiconductor layer 302 , and depositing the second electrode 400 comprise sputtering the alkali diffusion barrier layer 201 , the first transition metal layer 202 , the second transition metal layer 203 , the p-type absorber layer 301 , the n-type semiconductor layer 302 and one or more conductive films of the second electrode 400 over the substrate 100 (preferably a web substrate in this embodiment) in corresponding process modules of a plurality of independently isolated, connected process modules without breaking vacuum, while passing the web substrate 100 from an input module to an output module through the plurality of independently isolated, connected process modules such that the web substrate continuously extends from the input module to the output module while passing through the plurality of the independently isolated, connected process modules.
- Each of the process modules may include one or more sputtering targets for sputtering material over the web substrate 100 .
- a modular sputtering apparatus for making the solar cell may be used for depositing the layers.
- the apparatus is equipped with an input, or load, module 21 a and a symmetrical output, or unload, module 21 b .
- process modules 22 a , 22 b , 22 c and 22 d Between the input and output modules are process modules 22 a , 22 b , 22 c and 22 d .
- the number of process modules 22 may be varied to match the requirements of the device that is being produced.
- Each module has a pumping device 23 , such as vacuum pump, for example a high throughput turbomolecular pump, to provide the required vacuum and to handle the flow of process gases during the sputtering operation.
- Each module may have a number of pumps placed at other locations selected to provide optimum pumping of process gases.
- the modules are connected together at slit valves 24 , which contain very narrow low conductance isolation slots to prevent process gases from mixing between modules. These slots may be separately pumped if required to increase the isolation even further.
- Other module connectors 24 may also be used.
- a single large chamber may be internally segregated to effectively provide the module regions, if desired.
- Hollars discloses a vacuum sputtering apparatus having connected modules, and is incorporated herein by reference in its entirety.
- the web substrate 100 is moved throughout the machine by rollers 28 , or other devices. Additional guide rollers may be used. Rollers shown in FIG. 3A are schematic and non-limiting examples. Some rollers may be bowed to spread the web, some may move to provide web steering, some may provide web tension feedback to servo controllers, and others may be mere idlers to run the web in desired positions.
- the input spool 31 a and optional output spool 31 b thus are actively driven and controlled by feedback signals to keep the web in constant tension throughout the machine.
- the input and output modules may each contain a web splicing region or device 29 where the web 100 can be cut and spliced to a leader or trailer section to facilitate loading and unloading of the roll.
- the web 100 instead of being rolled up onto output spool 31 b , may be sliced into solar modules by the web splicing device 29 in the output module 21 b .
- the output spool 31 b may be omitted.
- some of the devices/steps may be omitted or replaced by any other suitable devices/steps.
- bowed rollers and/or steering rollers may be omitted in some embodiments.
- Heater arrays 30 are placed in locations where necessary to provide web heating depending upon process requirements. These heaters 30 may be a matrix of high temperature quartz lamps laid out across the width of the web. Infrared sensors provide a feedback signal to servo the lamp power and provide uniform heating across the web. In one embodiment, as shown in FIG. 3A , the heaters are placed on one side of the web 100 , and sputtering targets 27 a - e and 37 a - b are placed on the other side of the web 100 . Sputtering targets 27 and 37 may be mounted on dual cylindrical rotary magnetron(s), or planar magnetron(s) sputtering sources, or RF sputtering sources.
- the web substrate 100 may first pass by heater array 30 f in module 21 a , which provides at least enough heat to remove surface adsorbed water. Subsequently, the web can pass over roller 32 , which can be a special roller configured as a cylindrical rotary magnetron. This allows the surface of electrically conducting (metallic) webs to be continuously cleaned by DC, AC, or RF sputtering as it passes around the roller/magnetron. The sputtered web material is caught on shield 33 , which is periodically changed. Preferably, another roller/magnetron may be added (not shown) to clean the back surface of the web 100 .
- roller 32 can be a special roller configured as a cylindrical rotary magnetron. This allows the surface of electrically conducting (metallic) webs to be continuously cleaned by DC, AC, or RF sputtering as it passes around the roller/magnetron. The sputtered web material is caught on shield 33 , which is periodically changed.
- another roller/magnetron may be added (not shown) to
- Direct sputter cleaning of a web 100 will cause the same electrical bias to be present on the web throughout the machine, which, depending on the particular process involved, might be undesirable in other sections of the machine.
- the biasing can be avoided by sputter cleaning with linear ion guns instead of magnetrons, or the cleaning could be accomplished in a separate smaller machine prior to loading into this large roll coater. Also, a corona glow discharge treatment could be performed at this position without introducing an electrical bias.
- the web 100 passes into the process modules 22 a through valve 24 .
- the full stack of layers may be deposited in one continuous process.
- the first transition metal layer 202 may be sputtered in the process module 22 a over the web 100 , as illustrated in FIG. 3A (and previously in FIG. 1 ).
- the process module 22 a may include more than two pairs of targets, each pair of targets comprising a transition metal target 27 and an alkali-containing target 37 , arranged in such a way that the types of targets alternate and the series of targets end with a transition metal target.
- the alkali-containing target has a composition different from that of the transition metal target.
- the web 100 then passes into the next process module, 22 b , for deposition of the at least one p-type semiconductor absorber layer 301 .
- the step of depositing the at least one p-type semiconductor absorber layer 301 includes reactively alternating current (AC) magnetron sputtering the semiconductor absorber layer from at least one pair of two conductive targets 27 c 1 and 27 c 2 , in a sputtering atmosphere that comprises argon gas and a selenium-containing gas.
- the pair of two conductive targets 27 c 1 and 27 c 2 comprise the same targets.
- each of the at least two conductive targets 27 c 1 and 27 c 2 comprises copper, indium and gallium, or comprises copper, indium and aluminum.
- the selenium-containing gas may be hydrogen selenide or selenium vapor.
- targets 27 c 1 and 27 c 2 may comprise different materials from each other.
- the radiation heaters 30 maintain the web at the required process temperature, for example, around 400-800° C., for example around 500-600° C., which is preferable for the CIS based alloy deposition.
- At least one p-type semiconductor absorber layer 301 may comprise graded CIS based material.
- the process module 22 b further comprises at least two more pairs of targets ( 227 , and 327 ), as illustrated in FIG. 3B .
- the first magnetron pair 127 ( 27 c 1 and 27 c 2 ) are used to sputter a layer of copper indium diselenide while the next two pairs 227 , 327 of magnetrons targets ( 27 c 3 , 27 c 4 and 27 c 5 , 27 c 6 ) sputter deposit layers with increasing amounts of gallium (or aluminum), thus increasing and grading the band gap.
- the total number of targets pairs may be varied, for example may be 2-10 pairs, such as 3-5 pairs. This will grade the band gap from about 1 eV at the bottom to about 1.3 eV near the top of the layer. Details of depositing the graded CIS material is described in the Hollars published application, which is incorporated herein by reference in its entirety.
- the alkali diffusion barrier layers 201 may be sputtered over the substrate 100 in a process module added between the process modules 21 a and 22 a .
- the second transition metal layer 203 may be sputtered over the first transition metal layer 202 in a process module added between the process modules 22 a and 22 b .
- one or more process modules may be added to deposit additional barrier layers and/or adhesion layer to the stack, if desired.
- one or more process modules may be further added between the process modules 21 a and 22 a to sputter a back side protective layer over the back side of the substrate 100 before the first electrode 200 is deposited on the front side of the substrate.
- U.S. application Ser. No. 12/379,428 (Attorney Docket No. 075122/0139) titled “Protective Layer for large-scale production of thin-film solar cells” and filed on Feb. 20, 2009, which is hereby incorporated by reference, describes such deposition process.
- the web 100 may then pass into the process modules 22 c and 22 d , for depositing the n-type semiconductor layer 302 , and the transparent top electrode 400 , respectively.
- any suitable type of sputtering sources may be used, for example, rotating AC magnetrons, RF magnetrons, or planar magnetrons. Extra magnetron stations (not shown), or extra process modules (not shown) could be added for sputtering the optional one or more AR layers.
- the web 100 passes into output module 21 b , where it is either wound onto the take up spool 31 b , or sliced into solar cells using cutting apparatus 29 .
- the composition of the n-type semiconductor layer 302 is controlled by providing at least one of O 2 or H 2 into a reactive sputtering atmosphere to form a (In x Zn 1 ⁇ x ) 2+z (Se y S 1 ⁇ y ) 3+z (O,H) layer, where 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1 and 0 ⁇ z ⁇ 1.
- layer 302 include InS(O, H), ZnS(O, H), (In x Zn 1 ⁇ x )S(O,H) where 0 ⁇ x ⁇ 1.
- the oxygen and/or hydrogen content may comprise 10 atomic percent or less of the total semiconductor material, such as 0.001 to 5 atomic percent.
- the targets may comprise Zn, In or Zn-In alloy targets.
- the Group VI element(s) e.g., S or Se
- the oxygen and hydrogen may be supplied in a gas phase from a gas manifold or pipe which opens into the chamber 22 c .
- the sulfur may be provided together with the hydrogen as a gas, such as hydrogen sulfide gas rather than being evaporated into the sputtering atmosphere.
- the composition may be controlled by monitoring the reactive sputtering atmosphere and controlling the composition of the reactive sputtering atmosphere based on the results of the monitoring.
- the reactive sputtering atmosphere may be monitored by any suitable method, such as by plasma emission spectroscopy.
- the ratio of the metal (e.g., Zn and/or In) to hydrogen, oxygen, sulfur and/or selenium can be dynamically controlled based on the monitoring step by controlling the sputtering power, sputtering pressure, evaporation source temperature, hydrogen or oxygen gas flow rate, etc. to compensate for the metal loss at the absorber 301 layer interface and to improve band alignment of layers 301 and 302 .
- the reactive sputtering process may be controlled to make layer 302 slightly metal rich or Group VI deficient (e.g., more than one metal atom for each Group VI atom, including 1.01 to 1.2 metal atoms for each Group VI atom).
- Reactive sputtering permits different layer stoichiometries to be sputtered, which is not generally possible in RF sputtering of ceramic targets or wet plating of ZnS.
- layer 302 may be used in solar cells other than CIGS solar cells, such as solar cell having a II-VI absorber layer, such as CdTe, CdZnTeS, CdZnTeSe, etc., layers.
- an n-type ZnSe layer 302 may be formed by depositing a Zn or a Zn alloy layer over the absorber layer 301 and then diffusing the zinc into the top of the CIGS absorber layer 301 to form n-type Zn doped CIGS layer.
- the Zn layer contains sodium
- the sodium may be diffused into the CIGS absorber layer 301 instead of or in addition to diffusing sodium from the bottom electrode 200 .
- this embodiment may be used in combination with any one or more features of the previous embodiments described above.
- the sodium diffusion in this embodiment may take place only from the overlying zinc layer while the bottom electrode does not contain sodium.
- a p-type CIGS/n-type Zn doped CIGS p-n junction i.e., a CIGS homojunction
- the zinc diffusion takes place at a relatively low temperature, such as less than about 200 C to form zinc doped CIGS.
- a relatively low temperature such as less than about 200 C
- interdiffusion occurs between the adjacent zinc and the CIGS layers to form a zinc selenide layer above the CIGS layer.
- FIGS. 4A and 4B illustrate the above method of making a solar cell with a non-cadmium containing n-type semiconductor layer 302 .
- a first electrode 200 is deposited on a substrate 100 .
- the first electrode 200 may comprise an optional alkali diffusion barrier layer 201 , a first transition metal layer 202 and a second transition metal layer 203 .
- At least one p-type semiconductor absorber layer 301 is then deposited on the first electrode 200 .
- a metal or metal alloy sacrificial layer 303 is deposited on the absorber layer 301 .
- the layer 303 comprises Zn metal or a Zn:Na alloy.
- the n-type semiconductor layer 302 is then deposited on the layer 303 .
- the sacrificial layer may comprise a thickness of 1-5 nm, such as 1-3 nm.
- Layer 303 may be formed by sputtering from a zinc-based sputtering target, such DC or AC sputtering of a pure zinc target, or a Zn target and a Na containing target or one or more ZnNa binary alloy sputtering targets, in a preferably oxygen free environment, in an extra sputtering chamber added between chambers 22 b and 22 c in the apparatus shown in FIG. 3A .
- a zinc-based target means a target that comprises at least 30 weight percent zinc, such as 51-100 percent zinc.
- the composition of a ZnNa binary alloy sputtering target may comprise 0.01 to 4.0 weight percent sodium, more preferably 1.0 to 4.0 weight percent sodium and the balance being zinc and optionally less than 5 weight percent unavoidable impurities or intentionally added alloying elements.
- the n-type semiconductor layer 302 may then be sputtered over layer 303 in chamber 22 c .
- Layer 302 comprise any suitable n-type semiconductor material, such as (II,III)-VI semiconductor material comprises at least one of Zn and In, and at least one of S and Se, and optionally hydrogen and/or oxygen, including In-VI semiconductors, e.g.
- layer 302 comprises a semiconductor material which contains both In and Zn.
- the second electrode 400 may then be deposited on the n-type semiconductor layer 302 .
- the solar cell is then annealed as shown in FIG. 4B before or after layer 302 deposition to cause the diffusion of Zn from the layer 303 into the p-type semiconductor absorber layer 301 .
- the diffusing Zn reacts with Se in the p-type CIGS absorber layer 301 and forms an n-type semiconductor layer 305 (e.g., zinc doped CIGS) at the interface between the absorber layer 301 and the n-type semiconductor layer 302 .
- the annealing may be carried out at temperatures ranging from 150 to 500° C. for 20 to 1000 seconds, preferably 200 to 400 seconds, by thermal, laser or flash lamp annealing.
- the annealing may be carried out in the Zn layer 303 sputtering chamber or in a separate chamber downstream from the Zn layer sputtering chamber.
- the boundary between the p-type absorber layer 301 and the n-type semiconductor layer 305 provides the pn junction for the solar cell.
- the deposited Zn layer 303 may be entirely or partially diffused into the CIGS layer 301 by annealing to form layer 305 . For example, as shown in FIG. 4B , the entire sacrificial layer 303 is consumed.
- FIGS. 5A and 5B illustrate another embodiment of the invention.
- a first electrode 200 is deposited on a substrate 100 .
- the first electrode 200 may comprise an optional alkali diffusion barrier layer 201 , a first transition metal layer 202 and a second transition metal layer 203 .
- At least one p-type semiconductor absorber layer 301 is then deposited on the first electrode 200 .
- a Zn rich semiconductor buffer layer 306 is deposited on the absorber layer 301 instead, as shown in FIG. 5A .
- the first semiconductor buffer layer 306 is a Group VI deficient (II,III)-VI semiconductor layer deposited on the p-type semiconductor absorber layer 301 .
- a second (II,III)-VI semiconductor layer 308 is deposited on the first (II,III)-VI semiconductor layer 306 .
- the two (II,III)-VI semiconductor layers 306 , 308 have different compositions.
- the ratio of Group VI element to at least one of Group II or Group III elements (i.e., Group VI to metal atomic ratio) in the first (II,III)-VI semiconductor layer 306 is smaller than the ratio of the Group VI element to at least one of Group II or Group III elements in the second (II,III)-VI semiconductor layer 308 . That is, the first (II,III)-VI semiconductor layer 306 has a lower concentration of Group VI element than the second (II,III)-VI semiconductor layer 308 .
- the first (II,III)-VI semiconductor layer 306 is Group VI element poor (e.g., Zn rich) while the second (II,III)-VI semiconductor layer 308 is preferably stoichiometric.
- the first and second (II,III)-VI semiconductor layers 306 , 308 may be deposited by any suitable method, such as by reactive sputtering described above.
- the first (II,III)-VI semiconductor layer 306 is deposited by reactive sputtering in a sputtering atmosphere having a deficiency of Group VI element (e.g., sulfur) to form the Group VI element poor layer
- the second (II,III)-VI semiconductor layer 308 is deposited by reactive sputtering in a sputtering atmosphere having a stoichiometric ratio or excess of Group VI element.
- the first (II,III)-VI semiconductor layer 306 comprises at least one of Zn and In and at least one of S and Se.
- the second (II,III)-VI semiconductor layer 308 may comprise, for example, at least one of Zn and In, and at least one of S and Se.
- the p-type semiconductor absorber layer 301 may comprise CIGS:Na
- the first (II,III)-VI semiconductor layer 306 may comprise a sulfur poor (i.e., Zn rich) ZnS layer having a composition Zn 1 S 1 ⁇ x , where 0 ⁇ x ⁇ 0.3
- the second (II,III)-VI semiconductor layer 308 comprise a stoichiometric ZnS layer (e.g., Zn 1 S 1 ).
- the solar cell is then annealed as shown in FIG. 5B before or after the second electrode 400 has been deposited on the second (II,III)-VI semiconductor layer 308 .
- Annealing the solar cell causes diffusion of the excess Group II element, such as Zn, from the first (II,III)-VI semiconductor layer 306 into the p-type semiconductor absorber layer 301 .
- the diffusing Group II element reacts with the p-type semiconductor absorber layer 301 .
- n-type II-VI semiconductor layer 307 such as a n-type ZnSe layer 307 in the top portion of the p-type CIGS absorber layer 301 , at an interface between a resulting zinc sulfide layer and p-CIGS layer 301 .
- a relatively low temperature such as less than about 200 C
- n-type zinc doped CIGS layer 307 forms at the interface of layers 301 and 306 .
- interdiffusion occurs between the adjacent layers 306 and 301 to form an n-type zinc selenide layer 307 between the CIGS 301 and ZnS 306 layers.
- the step of annealing may further cause diffusion of Na from the p-CIGS:Na absorber layer 301 and/or from the semiconductor layer 306 if it contains sodium into the n-ZnSe layer 307 such that the n-ZnSe layer 307 comprises ZnSe:Na. If sodium is located interstitially rather than substitutionally on zinc sites in the lattice, then Na may act as an n-type rather than p-type dopant in ZnSe. As a result of the annealing, the first semiconductor layer 306 may be totally consumed (i.e., completely diffused into the CIGS layer 301 and/or combined with layer 308 ).
- a portion of the Group IV deficient first semiconductor layer 306 remains on top of the formed ZnSe layer 307 under the stoichiometric second (II,III) semiconductor layer 308 .
- the resulting zinc sulfide layer 306 comprises either a stoichiometric ZnS layer if sufficient zinc diffused into layer 307 or layer 306 remains a sulfur poor zinc sulfide layer if the zinc to sulfur atomic ratio in layer 306 remains greater than 1 after formation of layer 307 by zinc diffusion from layer 306 .
- the second electrode 400 may then deposited on the second (II,III)-VI semiconductor layer 308 before or after the annealing step.
- the reactive sputtering atmosphere may be monitored during deposition, such as with plasma emission spectroscopy, as described above.
- the reactive sputtering process may be controlled by providing at least one of S, Se, Zn, In, O 2 or H 2 into the reactive sputtering atmosphere based on the results of the monitoring during the deposition of the first and/or the second (II,III)-VI semiconductor layers 306 , 308 .
- the semiconductor layers 306 and/or 308 may optionally contain hydrogen and/or oxygen.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Sustainable Development (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Photovoltaic Devices (AREA)
Abstract
Description
- The present invention relates generally to the field of photovoltaic devices, and more specifically to CIGS thin-film solar cells comprising alkali and zinc doping.
- Copper indium diselenide (CuInSe2, or CIS) and its higher band gap variants copper indium gallium diselenide (Cu(In,Ga)Se2, or CIGS), copper indium aluminum diselenide (Cu(In,Al)Se2), copper indium gallium aluminum diselenide (Cu(In,Ga,Al)Se2) and any of these compounds with sulfur replacing some of the selenium represent a group of materials, referred to as copper indium selenide CIS based alloys, have desirable properties for use as the absorber layer in thin-film solar cells. To function as a solar absorber layer, these materials should be p-type semiconductors. This may be accomplished by establishing a slight deficiency in copper, while maintaining a chalcopyrite crystalline structure. In CIGS, gallium usually replaces 20% to 30% of the normal indium content to raise the band gap; however, there are significant and useful variations outside of this range. If gallium is replaced by aluminum, smaller amounts of aluminum are used to achieve the same band gap.
- One embodiment of this invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode. The p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material. The method also includes depositing by reactive sputtering an n-type In-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing a second electrode over the n-type In-VI semiconductor layer.
- Another embodiment of the invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode. The p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material. The method also includes depositing by reactive sputtering a first (II,III)-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing by reactive sputtering a second (II,III)-VI semiconductor layer over the first (II,III)-VI semiconductor layer, wherein a ratio of Group VI element to at least one of Group II or Group III elements in the first (II,III)-VI semiconductor layer is smaller than the ratio of Group VI element to at least one of Group II or Group III elements in the second (II,III)-VI semiconductor layer.
- Another embodiment of the invention provides a method of manufacturing a solar cell including providing a substrate, depositing a first electrode over the substrate and depositing at least one p-type semiconductor absorber layer over the first electrode. The p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material. The method also includes depositing by reactive sputtering an n-type II-III-VI semiconductor layer over the at least one p-type semiconductor absorber layer and depositing a second electrode of the n-type semiconductor layer.
- Another embodiment of the invention provides a solar cell including a substrate, a first electrode over the substrate and at least one p-type semiconductor absorber layer over the first electrode, wherein the p-type semiconductor absorber layer comprises a copper indium selenide (CIS) based alloy material. The solar cell also includes a first sodium doped n-type (II,III)-VI semiconductor layer on the at least one p-type semiconductor absorber layer, a second n-type (II,III)-VI semiconductor layer over the first n-type (II,III)-VI semiconductor layer and a second electrode over the a second n-type (II,III)-VI semiconductor layer.
-
FIG. 1 is a schematic side cross-sectional view of a CIS based solar cell according to one embodiment of the invention. -
FIG. 2 shows a highly simplified schematic diagram of a top view of a sputtering apparatus that can be used to forming a first transition metal layer such as an alkali-containing transition metal layer, for example, a sodium-containing molybdenum film. -
FIG. 3A shows a highly simplified schematic diagram of a top view of a modular sputtering apparatus that can be used to manufacture the solar cell depicted inFIG. 1 . FIG. 3B illustrates schematically the use of three sets of dual magnetrons to increase the deposition rate and grade the composition of the CIS layer to vary its band gap. -
FIGS. 4A and 4B are schematic side cross-sectional views of an in-process CIS based solar cell according to another embodiment of the invention. -
FIGS. 5A and 5B are schematic side cross-sectional views of an in-process CIS based solar cell according to another embodiment of the invention. - Conventional CIS or CIGS solar cells include a CdS buffer layer between the CIS or CIGS absorber layer and the top transparent conductive oxide electrode. However, cadmium is a highly toxic material. Long term or chronic exposure, such as in the workplace, has been linked to kidney and lung disorders. Even short term exposure may lead to flu-like symptoms, such as fever, chills, muscle aches. Thus, it would be advantageous to replace the CdS buffer layer with a layer comprising less toxic materials.
- One embodiment of this invention provides a solar cell comprising a substrate, a first electrode located over the substrate, where the first electrode comprises a first transition metal layer, at least one p-type semiconductor absorber layer located over the first electrode, an n-type In-VI semiconductor layer located over the p-type semiconductor absorber layer, and a second electrode located over the n-type semiconductor layer.
- As illustrated in
FIG. 1 , one embodiment of the invention provides a solar cell contains asubstrate 100 and a first (lower)electrode 200. Thefirst electrode 200 comprises a firsttransition metal layer 202 that contains (i) an alkali element or an alkali compound and (ii) a lattice distortion element or a lattice distortion compound. Alternatively, the firsttransition metal layer 202 contains an alkali element or an alkali compound but substantially free of the lattice distortion element or compound. - The transition metal of the first
transition metal layer 202 may be any suitable transition metal, for example but not limited to Mo, W, Ta, V, Ti, Nb, and Zr. The alkali element or alkali compound may comprise one or more of Li, Na, and K. The lattice distortion element or the lattice distortion compound may be any suitable element or compound, for example, oxygen, nitrogen, sulfur, selenium, an oxide, a nitride, a sulfide, a selenide, an organometallic compound (e.g. a metallocene, a metal carbonyl such as tungsten pentacyonyl and tungsten hexacarbonyl, and the like), or a combination thereof. For example, in a non-limiting example, the firsttransition metal layer 202 may comprise at least 59 atomic percent molybdenum, 5 to 40 atomic percent oxygen such as around 20 atomic percent oxygen, and 0.01 to 1.5 atomic percent sodium. In some embodiments, the firsttransition metal layer 202 may comprise 1021 to 1023 atoms/cm3 sodium. - The first
transition metal layer 202 may have a thickness of 100 to 500 nm, for example 200 to 400 nm such as around 300 nm. In some embodiments, the firsttransition metal layer 202 may comprise multiple sub-layers, for example 1 to 20 sub-layers such as 1 to 10 sub-layers. Each sub-layer has a different sodium concentration, resulting in a graded sodium concentration profile within the firsttransition metal layer 202. - In some embodiments, the lattice distortion element or the lattice distortion compound has a crystal structure different from that of the first transition metal layer to distort a polycrystalline lattice of the first
transition metal layer 202. In some embodiments, when the transition metal is molybdenum, the lattice distortion element may be oxygen, forming the firsttransition metal layer 202 of body centered cubic Mo lattice distorted by face centered cubic oxide compositions, such as MoO2 and MoO3. Without wishing to be bounded to a particular theory, the density of the firsttransition metal layer 202 may be reduced due to a greater interplanar spacing as a result of the lattice distortion. In some other embodiments, the lattice distortion element may exist as substitutional or interstitial atoms, rather than forming a compound with other impurities or the matrix of the firsttransition metal layer 202. - Optionally, the
first electrode 200 of the solar cell may comprise an alkalidiffusion barrier layer 201 located between thesubstrate 100 and the firsttransition metal layer 202, and/or a secondtransition metal layer 203 located over the firsttransition metal layer 202. Additional adhesion layer (not shown) may be further disposed between theelectrode 200 and thesubstrate 100, for example between the optional alkalidiffusion barrier layer 201 and thesubstrate 100. - The optional alkali
diffusion barrier layer 201 and secondtransition metal layer 203 may comprise any suitable materials. For example, they may be independently selected from a group consisting Mo, W, Ta, V, Ti, Nb, Zr, Cr, TiN, ZrN, TaN, VN, or combinations thereof. - In some embodiments, while the alkali
diffusion barrier layer 201 is oxygen free, the firsttransition metal layer 202 and/or the secondtransition metal layer 203 may contain oxygen and/or be deposited at a higher pressure than the alkalidiffusion barrier layer 201 to achieve a lower density than the alkalidiffusion barrier layer 201. Of course, other impurity elements (e.g. lattice distortion elements or the lattice distortion compounds described above), instead of or in addition to oxygen, may be contained in the secondtransition metal layer 202 and/or the secondtransition metal layer 203 to reduce the density thereof. - The alkali
diffusion barrier layer 201 may be in compressive stress and have a thickness greater than that of the secondtransition metal layer 203. For example, the alkalidiffusion barrier layer 201 may have a thickness of around 100 to 400 nm such as 100 to 200 nm, while the secondtransition metal layer 203 has a thickness of around 50 to 200 nm such as 50 to 100 nm. Whilelayer 201 may comprise molybdenum, in alternative embodiments it may comprise other materials, such as TiN or other barrier materials listed above. - The higher density and greater thickness of the alkali
diffusion barrier layer 201 substantially reduces/prevents alkali diffusion from the firsttransition metal layer 202 into thesubstrate 100. On the other hand, the secondtransition metal layer 203 has a higher porosity than the alkalidiffusion barrier layer 201 and permits alkali diffusion from the firsttransition metal layer 202 into the p-typesemiconductor absorber layer 301. In these embodiments, alkali may diffuse from the firsttransition metal layer 202, through the lower density secondtransition metal layer 203, into the at least one p-typesemiconductor absorber layer 301 during and/or after the step of depositing the at least one p-typesemiconductor absorber layer 301. - Alternatively, the optional alkali
diffusion barrier layer 201 and/or optional secondtransition metal layer 203 may be omitted. When the optional secondtransition metal layer 203 is omitted, the at least one p-typesemiconductor absorber layer 301 is deposited over the firsttransition metal layer 202, and alkali may diffuse from the firsttransition metal layer 202 into the at least one p-typesemiconductor absorber layer 301 during or after the deposition of the at least one p-typesemiconductor absorber layer 301. - In preferred embodiments, the p-type
semiconductor absorber layer 301 may comprise a CIS based alloy material selected from copper indium selenide, copper indium gallium selenide, copper indium aluminum selenide, or combinations thereof.Layer 301 may have a stoichiometric composition having a Group I to Group III to Group VI atomic ratio of about 1:1:2, or a non-stoichiometric composition having an atomic ratio of other than about 1:1:2. Preferably,layer 301 is slightly copper deficient and has a slightly less than one copper atom for each one of Group III atom and each two of Group VI atoms. The step of depositing the at least one p-typesemiconductor absorber layer 301 may comprise reactively AC sputtering the semiconductor absorber layer from at least two electrically conductive targets in a sputtering atmosphere that comprises argon gas and a selenium containing gas (e.g. selenium vapor or hydrogen selenide). For example, each of the at least two electrically conductive targets comprises copper, indium and gallium; and the CIS based alloy material comprises copper indium gallium diselenide. In one embodiment, the p-typesemiconductor absorber layer 301 may comprise 0.03 to 1.5 atomic percent sodium diffused from the firsttransition metal layer 202. As described above, sodium impurities may diffuse from the firsttransition metal layer 202 to the CIS basedalloy layer 301. In one embodiment, the sodium impurities may concentrate at the grain boundaries of CIS based alloy, and may have a concentration as high as 1021 to 1022 atoms/cm3. - In an embodiment, an n-
type semiconductor layer 302 may then be deposited over the p-typesemiconductor absorber layer 301. In alternative embodiments discussed in more detail below, one or more layers are deposited on theabsorber layer 301 and then annealed to form the n-type semiconductor layer. The n-type semiconductor layer 302 may comprise any suitable n-type semiconductor materials. Suitable materials for the n-type semiconductor layer 302 include but are not limited to In-VI semiconductors, such as In2Se3, In2S3, In2(Se1−xSx)3, (In2±y Zn1±y)Se4, (In2±yZn1±y)S4 or (In2±yZn1±y)(Se1−xSx)4, where 0<x<1, 0≦y≦1 and (InxZn1−x)2+z (SeyS1−y)3+z, wherein 0<x≦1, 0≦y≦1, and 0≦z≦1. Other suitable semiconductor materials include (II,III)-VI semiconductors, such as semiconductor materials which include at least one of Zn and In, and at least one of S and Se, such as ZnSe:Na and Zn(SeyS1−y):Na, wherein 0≦y≦1. As used herein, the term “(II,III)-VI semiconductor” includes semiconductors which include: a) a Group VIA element (e.g., S and/or Se), and b) either a Group IIB element (e.g., Zn) or a Group IIIA element (e.g., In) or both a Group IIB and a Group IIIA element (e.g., both Zn and In). Preferably, but not necessarily, the VI semiconductor excludes cadmium other than unavoidable Cd impurity. As used herein, the term “II-III-VI semiconductor” includes semiconductors which include: a) a Group VIA element (e.g., S and/or Se), and b) a Group IIB element (e.g., Zn), and c) a Group IIIA element (e.g., In). - After the n-
type semiconductor layer 302 is deposited, asecond electrode 400, also referred to as a transparent top electrode, is further deposited over the n-type semiconductor layer 302. The transparenttop electrode 400 may comprise multiple transparent conductive layers, for example, but not limited to, an Indium Tin Oxide (ITO)layer 402 located over an optional intrinsic Zinc Oxide or a resistive Aluminum Zinc Oxide (AZO, also referred to as RAZO)layer 401. Of course, the transparenttop electrode 400 may comprise any other suitable materials, for example, doped ZnO or SnO. - Optionally, one or more antireflection (AR) films (not shown) may be deposited over the transparent
top electrode 400, to optimize the light absorption in the cell, and/or current collection grid lines may be deposited over the top conducting oxide. - Alternatively, the solar cell may be formed in reverse order. In this configuration, a transparent electrode is deposited over a substrate, followed by depositing an n-type semiconductor layer over the transparent electrode, depositing at least one p-type semiconductor absorber layer over the n-type semiconductor layer, depositing a first transition metal layer over the at least one p-type semiconductor absorber layer, and optionally depositing a second transition metal layer between the first transition metal layer and the p-type semiconductor absorber layer and/or depositing a alkali
diffusion barrier layer 201 over the firsttransition metal layer 202. The substrate may be a transparent substrate (e.g., glass) or opaque (e.g., metal). If the substrate used is opaque, then the initial substrate may be delaminated after the steps of depositing the stack of the above described layers, and then bonding a glass or other transparent substrate to the transparent electrode of the stack. - A solar cell described above may be fabricated by any suitable methods. In one embodiment, a method of manufacturing such a solar cell comprising providing a
substrate 100, depositing afirst electrode 200 over thesubstrate 100, depositing at least one p-typesemiconductor absorber layer 301 over thefirst electrode 200, depositing an n-type semiconductor layer 302 over the p-typesemiconductor absorber layer 301, and depositing asecond electrode 400 over the n-type semiconductor layer 302. The step of depositing thefirst electrode 200 comprises depositing the firsttransition metal layer 202. While sputtering was described as the preferred method for depositing all layers onto the substrate, some layers may be deposited by MBE, CVD, evaporation, plating, etc. In some embodiments, one or more sputtering steps may be reactive sputtering. - In some embodiments, the lattice distortion element or compound may be contained in at least one of the sputtering target used for sputtering the first
transition metal layer 202. For example, in some embodiments the step of sputtering the firsttransition metal layer 202 comprises sputtering from a target comprising a combination of the transition metal, the alkali element/compound, and the lattice distortion element/compound, for example, a sodium molybdate target. In general and without being limited to a specific composition, the target may comprise 5 to 40 atomic percent oxygen, such as around 20 atomic percent oxygen, 0.01 to 1.5 atomic percent sodium, and balance molybdenum. In some other embodiments, the step of sputtering the firsttransition metal layer 202 comprises sputtering from at least one pair of sputtering targets having different compositions from each other. The at least one pair of sputtering targets are selected from: (i) a first molybdenum target and a second sodium molybdate or sodium oxide target; (ii) a first molybdenum oxide target (e.g., a molybdenum target containing 5 to 40 atomic percent oxygen, such as around 20 atomic percent oxygen) and a second sodium selenide, sodium fluoride, sodium selenide or sodium sulfate target; or (iii) a first molybdenum target and a second sodium target in an oxygen containing reactive sputtering system. Preferably, the at least one pair of targets is located in the same vacuum chamber of a magnetron sputtering system. - Alternatively, reactive sputtering may be used to introduce the lattice distortion element or compound, such as oxygen, nitrogen, etc., from a gas phase instead of or in addition to from a sputtering target. A target comprising both transition metal and alkali element/compound, or a pair of target comprising one transition metal target (e.g. a Mo target) and one alkali element/compound target (e.g. a NaF target) may be used. In one embodiment, the transition metal target may be substantially free of alkali. As used herein, the term “substantially free of alkali” means that no alkali metal or other alkali-containing material is intentionally alloyed or doped, but unavoidable impurities of alkali may present. If desired, more than two targets may be used to sputter the first
transition metal layer 202. - For example, by using a sputtering apparatus illustrated in
FIG. 2 , the first transition metal layer (not shown inFIG. 2 , and referred to aslayer 202 inFIGS. 1 ) may be deposited over asubstrate 100. Targets comprising an alkali-containing material (e.g., targets 37 a and 37 b) and targets comprising a transition metal (e.g., 27 a and 27 b) are located in asputtering process module 22 a, such as a vacuum chamber. In this non-limiting example, thetransition metal targets DC power sources 7, and the alkali-containingtargets RF generators 6 throughmatching networks 5. The target types alternate and end with a transition metal target, forexample target 27 b as shown inFIG. 2 . The distance between the adjacent targets is small enough such that asufficient overlap 9 may exist between the alternating transition and metal alkali containing fluxes and thus enhance the intermixing of the transition metal and the alkali-containing material during depositing the alkali-containing transition metal layer. - In some embodiments, the step of depositing the first
transition metal layer 202 may be conducted in an oxygen and/or nitrogen rich environment, and may comprise DC sputtering the transition metal from the first target and pulsed DC sputtering, AC sputtering, or RF sputtering the alkali compound from the second target. Any suitable variations of the sputtering methods may be used. For example, for electrically insulating second target materials, AC sputtering refers to any variation of AC sputtering methods that may be used to for insulating target sputtering, such as medium frequency AC sputtering or AC pairs sputtering. In one embodiment, the step of depositing the first transition metal layer may comprise DC sputtering a first target comprising a transition metal, such as molybdenum, and pulsed DC sputtering, AC sputtering, or RF sputtering a second target comprising alkali-containing material, such as a sodium-containing material, in an oxygen rich sputtering environment. - The
substrate 100 may be a foil web, for example, a metal web substrate, a polymer web substrate, or a polymer coated metal web substrate, and may be continuously passing through the sputteringmodule 22 a during the sputtering process, following the direction of the imaginary arrow along theweb 100. Any suitable materials may be used for the foil web. For example, metal (e.g., stainless steel, aluminum, or titanium) or thermally stable polymers (e.g., polyimide or the like) may be used. Thefoil web 100 may move at a constant or variable rate to enhance intermixing. - The sodium-containing material may comprise any material containing sodium, for example alloys or compounds of sodium with one or more of selenium, sulfur, oxygen, nitrogen or barrier metal (such as molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium), such as sodium fluoride, sodium molybdate, sodium fluoride, sodium selenide, sodium hydroxide, sodium oxide, sodium sulfate, sodium tungstate, sodium selenate, sodium selenite, sodium sulfide, sodium sulfite, sodium titanate, sodium metavanadate, sodium orthovanadate, or combinations thereof. Alloys or compounds of lithium and/or potassium may be also used, for example but not limited to alloys or compounds of lithium or potassium with one or more of selenium, sulfur, oxygen, nitrogen, molybdenum, tungsten, tantalum, vanadium, titanium, niobium or zirconium. The transition metal target may comprise a pure metal target, a metal alloy target, a metal oxide target (such as a molybdenum oxide target), etc.
- In one embodiment, the transition metal is molybdenum, and the first
transition metal layer 202 comprises molybdenum intentionally doped with oxygen and at least one alkali element, such as sodium. The oxygen can be omitted or replaced with any lattice distortion elements. Likewise, sodium may be replaced in whole or in part by lithium or potassium. Thefirst transition layer 202 may contain elements other than molybdenum, oxygen and sodium, such as other materials that are diffused into this layer during deposition, such as indium, copper, selenium and/or barrier layer metals. - The amount of sodium diffused into the at least one p-type
semiconductor absorber layer 301 may be tuned by independently controlling the thickness of deposited molybdenum sublayers and the thickness of sodium-containing sublayers in the first transition layer, by independently tuning the sputtering rate of the first target comprising molybdenum and the sputtering rate of the second target comprising sodium. A variable sodium content as a function of thickness in the sodium-containing molybdenum layer may also be generated by independently controlling the thickness of the deposited molybdenum sublayers and the thickness of the sodium-containing sublayers in the firsttransition metal layer 202. The molybdenum sublayers and the sodium-containing sublayers may become intermixed, forming a continuous sodium-containing molybdenum layer, during at least one of the steps of depositing the firsttransition metal layer 202, depositing the at least one p-typesemiconductor absorber layer 301, or an optional post-deposition annealing process. - Optionally, the step of depositing the
first electrode 200 further comprises depositing an alkalidiffusion barrier layer 201 between thesubstrate 100 and the firsttransition metal layer 202, and depositing a secondtransition metal layer 203 over the firsttransition metal layer 202. In some embodiments, the step of sputtering the alkalidiffusion barrier layer 201 occurs at a lower pressure than the step of sputtering the secondtransition metal layer 203. - In some embodiments, the step of sputtering the alkali
diffusion barrier layer 201 occurs under a first sputtering environment in a first vacuum chamber of a magnetron sputtering system, while the step of sputtering the secondtransition metal layer 203 occurs under a second sputtering environment in a second vacuum chamber of the magnetron sputtering system different from the first vacuum chamber. The second sputtering environment differs from the first sputtering environment in at least one of argon pressure, oxygen pressure, or nitrogen pressure. For example, the step of sputtering the alkalidiffusion barrier layer 201 may occur in an oxygen free atmosphere, while the step of sputtering the secondtransition metal layer 203 occurs in an oxygen containing atmosphere. For example, in some embodiments, the step of depositing the alkalidiffusion barrier layer 201 may comprise sputtering from a metal target under 0.8 to 1.2 mtorr such as around 1 mtorr in an inert environment, while the step of depositing the secondtransition metal layer 203 comprises sputtering from an transition metal target under 2 to 8 mtorr in an oxygen and/or nitrogen rich environment. The sputtering power used for depositing the alkalidiffusion barrier layer 201 and depositing the secondtransition metal layer 203 may also be different. For example, the sputtering power used for depositing the alkalidiffusion barrier layer 201 may be higher than that used for depositing the secondtransition metal layer 203. - The step of sputtering the first
transition metal layer 202 may occur in the first or the second vacuum chamber. For example, a firsttransition metal layer 202 containing lattice distortion element/compound(s) may be deposited in the second vacuum chamber in which the secondtransition metal layer 203 is deposited. In some other embodiments, when a firsttransition metal layer 202 free of lattice distortion element/compound(s) is desired, the firsttransition metal layer 202 may be deposited in the first vacuum chamber in which the alkalidiffusion barrier layer 201 is deposited. Alternatively, the step of sputtering the firsttransition metal layer 202 may occur in a third vacuum chamber of the magnetron sputtering system different from the first and the second vacuum chambers. - In some embodiments, the step of depositing the first electrode 200 (comprising depositing the alkali
diffusion barrier layer 201, depositing the firsttransition metal layer 202 and depositing the second transition metal layer 203) comprises sputtering the alkalidiffusion barrier layer 201, sputtering the firsttransition metal layer 202, and sputtering the secondtransition metal layer 203 in the same sputtering apparatus. - More preferably, the steps of depositing the
first electrode 200, depositing the at least one p-typesemiconductor absorber layer 301, depositing the n-type semiconductor layer 302, and depositing thesecond electrode 400 comprise sputtering the alkalidiffusion barrier layer 201, the firsttransition metal layer 202, the secondtransition metal layer 203, the p-type absorber layer 301, the n-type semiconductor layer 302 and one or more conductive films of thesecond electrode 400 over the substrate 100 (preferably a web substrate in this embodiment) in corresponding process modules of a plurality of independently isolated, connected process modules without breaking vacuum, while passing theweb substrate 100 from an input module to an output module through the plurality of independently isolated, connected process modules such that the web substrate continuously extends from the input module to the output module while passing through the plurality of the independently isolated, connected process modules. Each of the process modules may include one or more sputtering targets for sputtering material over theweb substrate 100. - For example, a modular sputtering apparatus for making the solar cell, as illustrated in
FIG. 3A (top view), may be used for depositing the layers. The apparatus is equipped with an input, or load,module 21 a and a symmetrical output, or unload,module 21 b. Between the input and output modules areprocess modules pumping device 23, such as vacuum pump, for example a high throughput turbomolecular pump, to provide the required vacuum and to handle the flow of process gases during the sputtering operation. Each module may have a number of pumps placed at other locations selected to provide optimum pumping of process gases. The modules are connected together atslit valves 24, which contain very narrow low conductance isolation slots to prevent process gases from mixing between modules. These slots may be separately pumped if required to increase the isolation even further.Other module connectors 24 may also be used. Alternatively, a single large chamber may be internally segregated to effectively provide the module regions, if desired. U.S. Pat. No. 7,544,884 (“Hollars”) discloses a vacuum sputtering apparatus having connected modules, and is incorporated herein by reference in its entirety. - The
web substrate 100 is moved throughout the machine byrollers 28, or other devices. Additional guide rollers may be used. Rollers shown inFIG. 3A are schematic and non-limiting examples. Some rollers may be bowed to spread the web, some may move to provide web steering, some may provide web tension feedback to servo controllers, and others may be mere idlers to run the web in desired positions. Theinput spool 31 a andoptional output spool 31 b thus are actively driven and controlled by feedback signals to keep the web in constant tension throughout the machine. In addition, the input and output modules may each contain a web splicing region ordevice 29 where theweb 100 can be cut and spliced to a leader or trailer section to facilitate loading and unloading of the roll. In some embodiments, theweb 100, instead of being rolled up ontooutput spool 31 b, may be sliced into solar modules by theweb splicing device 29 in theoutput module 21 b. In these embodiments, theoutput spool 31 b may be omitted. As a non-limiting example, some of the devices/steps may be omitted or replaced by any other suitable devices/steps. For example, bowed rollers and/or steering rollers may be omitted in some embodiments. -
Heater arrays 30 are placed in locations where necessary to provide web heating depending upon process requirements. Theseheaters 30 may be a matrix of high temperature quartz lamps laid out across the width of the web. Infrared sensors provide a feedback signal to servo the lamp power and provide uniform heating across the web. In one embodiment, as shown inFIG. 3A , the heaters are placed on one side of theweb 100, and sputtering targets 27 a-e and 37 a-b are placed on the other side of theweb 100. Sputtering targets 27 and 37 may be mounted on dual cylindrical rotary magnetron(s), or planar magnetron(s) sputtering sources, or RF sputtering sources. - After being pre-cleaned, the
web substrate 100 may first pass byheater array 30 f inmodule 21 a, which provides at least enough heat to remove surface adsorbed water. Subsequently, the web can pass overroller 32, which can be a special roller configured as a cylindrical rotary magnetron. This allows the surface of electrically conducting (metallic) webs to be continuously cleaned by DC, AC, or RF sputtering as it passes around the roller/magnetron. The sputtered web material is caught onshield 33, which is periodically changed. Preferably, another roller/magnetron may be added (not shown) to clean the back surface of theweb 100. Direct sputter cleaning of aweb 100 will cause the same electrical bias to be present on the web throughout the machine, which, depending on the particular process involved, might be undesirable in other sections of the machine. The biasing can be avoided by sputter cleaning with linear ion guns instead of magnetrons, or the cleaning could be accomplished in a separate smaller machine prior to loading into this large roll coater. Also, a corona glow discharge treatment could be performed at this position without introducing an electrical bias. - Next, the
web 100 passes into theprocess modules 22 a throughvalve 24. Following the direction of the imaginary arrows along theweb 100, the full stack of layers may be deposited in one continuous process. The firsttransition metal layer 202 may be sputtered in theprocess module 22 a over theweb 100, as illustrated inFIG. 3A (and previously inFIG. 1 ). Optionally, theprocess module 22 a may include more than two pairs of targets, each pair of targets comprising a transition metal target 27 and an alkali-containing target 37, arranged in such a way that the types of targets alternate and the series of targets end with a transition metal target. The alkali-containing target has a composition different from that of the transition metal target. - The
web 100 then passes into the next process module, 22 b, for deposition of the at least one p-typesemiconductor absorber layer 301. In a preferred embodiment shown inFIG. 3A , the step of depositing the at least one p-typesemiconductor absorber layer 301 includes reactively alternating current (AC) magnetron sputtering the semiconductor absorber layer from at least one pair of two conductive targets 27 c 1 and 27 c 2, in a sputtering atmosphere that comprises argon gas and a selenium-containing gas. In some embodiment, the pair of two conductive targets 27 c 1 and 27 c 2 comprise the same targets. For example, each of the at least two conductive targets 27 c 1 and 27 c 2 comprises copper, indium and gallium, or comprises copper, indium and aluminum. The selenium-containing gas may be hydrogen selenide or selenium vapor. In other embodiments, targets 27 c 1 and 27 c 2 may comprise different materials from each other. Theradiation heaters 30 maintain the web at the required process temperature, for example, around 400-800° C., for example around 500-600° C., which is preferable for the CIS based alloy deposition. - In some embodiments, at least one p-type
semiconductor absorber layer 301 may comprise graded CIS based material. In this embodiment, theprocess module 22 b further comprises at least two more pairs of targets (227, and 327), as illustrated inFIG. 3B . The first magnetron pair 127 (27 c 1 and 27 c 2) are used to sputter a layer of copper indium diselenide while the next twopairs - Optionally, the alkali diffusion barrier layers 201 may be sputtered over the
substrate 100 in a process module added between theprocess modules transition metal layer 203 may be sputtered over the firsttransition metal layer 202 in a process module added between theprocess modules - In some embodiments, one or more process modules (not shown) may be further added between the
process modules substrate 100 before thefirst electrode 200 is deposited on the front side of the substrate. U.S. application Ser. No. 12/379,428 (Attorney Docket No. 075122/0139) titled “Protective Layer for large-scale production of thin-film solar cells” and filed on Feb. 20, 2009, which is hereby incorporated by reference, describes such deposition process. Theweb 100 may then pass into theprocess modules type semiconductor layer 302, and the transparenttop electrode 400, respectively. Any suitable type of sputtering sources may be used, for example, rotating AC magnetrons, RF magnetrons, or planar magnetrons. Extra magnetron stations (not shown), or extra process modules (not shown) could be added for sputtering the optional one or more AR layers. Finally, theweb 100 passes intooutput module 21 b, where it is either wound onto the take upspool 31 b, or sliced into solar cells using cuttingapparatus 29. - In an embodiment, the composition of the n-
type semiconductor layer 302 is controlled by providing at least one of O2 or H2 into a reactive sputtering atmosphere to form a (InxZn1−x)2+z (SeyS1−y)3+z (O,H) layer, where 0≦x≦1, 0≦y≦1 and 0≦z≦1. Examples oflayer 302 include InS(O, H), ZnS(O, H), (InxZn1−x)S(O,H) where 0<x<1. In this embodiment, the oxygen and/or hydrogen content may comprise 10 atomic percent or less of the total semiconductor material, such as 0.001 to 5 atomic percent. In the process of sputteringlayer 302 inchamber 22 c, the targets may comprise Zn, In or Zn-In alloy targets. The Group VI element(s) (e.g., S or Se) may be evaporated from evaporation source(s), such as evaporation pots and spargers. The oxygen and hydrogen may be supplied in a gas phase from a gas manifold or pipe which opens into thechamber 22 c. Alternatively, the sulfur may be provided together with the hydrogen as a gas, such as hydrogen sulfide gas rather than being evaporated into the sputtering atmosphere. - The composition may be controlled by monitoring the reactive sputtering atmosphere and controlling the composition of the reactive sputtering atmosphere based on the results of the monitoring. The reactive sputtering atmosphere may be monitored by any suitable method, such as by plasma emission spectroscopy. The ratio of the metal (e.g., Zn and/or In) to hydrogen, oxygen, sulfur and/or selenium can be dynamically controlled based on the monitoring step by controlling the sputtering power, sputtering pressure, evaporation source temperature, hydrogen or oxygen gas flow rate, etc. to compensate for the metal loss at the
absorber 301 layer interface and to improve band alignment oflayers layer 302 slightly metal rich or Group VI deficient (e.g., more than one metal atom for each Group VI atom, including 1.01 to 1.2 metal atoms for each Group VI atom). Reactive sputtering permits different layer stoichiometries to be sputtered, which is not generally possible in RF sputtering of ceramic targets or wet plating of ZnS. It should be noted thatlayer 302 may be used in solar cells other than CIGS solar cells, such as solar cell having a II-VI absorber layer, such as CdTe, CdZnTeS, CdZnTeSe, etc., layers. - In another embodiment, an n-
type ZnSe layer 302 may be formed by depositing a Zn or a Zn alloy layer over theabsorber layer 301 and then diffusing the zinc into the top of theCIGS absorber layer 301 to form n-type Zn doped CIGS layer. In addition, if the Zn layer contains sodium, then the sodium may be diffused into theCIGS absorber layer 301 instead of or in addition to diffusing sodium from thebottom electrode 200. Thus, this embodiment may be used in combination with any one or more features of the previous embodiments described above. Alternatively, the sodium diffusion in this embodiment may take place only from the overlying zinc layer while the bottom electrode does not contain sodium. Furthermore, in this embodiment, a p-type CIGS/n-type Zn doped CIGS p-n junction (i.e., a CIGS homojunction) is formed, as described in U.S. Pat. No. 7,544,884, which is incorporated herein by reference in its entirety. Preferably, the zinc diffusion takes place at a relatively low temperature, such as less than about 200 C to form zinc doped CIGS. In contrast, at higher temperatures, such as above 200 C, interdiffusion occurs between the adjacent zinc and the CIGS layers to form a zinc selenide layer above the CIGS layer. -
FIGS. 4A and 4B illustrate the above method of making a solar cell with a non-cadmium containing n-type semiconductor layer 302. Similar to the embodiment illustrated inFIG. 1 , afirst electrode 200 is deposited on asubstrate 100. Thefirst electrode 200 may comprise an optional alkalidiffusion barrier layer 201, a firsttransition metal layer 202 and a secondtransition metal layer 203. At least one p-typesemiconductor absorber layer 301 is then deposited on thefirst electrode 200. - At this point, the method diverges from the embodiment illustrated in
FIG. 1 . Rather than depositing the n-type semiconductor layer 302 on theabsorber layer 301, a metal or metal alloysacrificial layer 303 is deposited on theabsorber layer 301. In an embodiment, thelayer 303 comprises Zn metal or a Zn:Na alloy. The n-type semiconductor layer 302 is then deposited on thelayer 303. The sacrificial layer may comprise a thickness of 1-5 nm, such as 1-3 nm.Layer 303 may be formed by sputtering from a zinc-based sputtering target, such DC or AC sputtering of a pure zinc target, or a Zn target and a Na containing target or one or more ZnNa binary alloy sputtering targets, in a preferably oxygen free environment, in an extra sputtering chamber added betweenchambers FIG. 3A . For the purposes of this disclosure, a zinc-based target means a target that comprises at least 30 weight percent zinc, such as 51-100 percent zinc. The composition of a ZnNa binary alloy sputtering target may comprise 0.01 to 4.0 weight percent sodium, more preferably 1.0 to 4.0 weight percent sodium and the balance being zinc and optionally less than 5 weight percent unavoidable impurities or intentionally added alloying elements. As in the embodiment illustrated inFIG. 1 , the n-type semiconductor layer 302 may then be sputtered overlayer 303 inchamber 22 c.Layer 302 comprise any suitable n-type semiconductor material, such as (II,III)-VI semiconductor material comprises at least one of Zn and In, and at least one of S and Se, and optionally hydrogen and/or oxygen, including In-VI semiconductors, e.g. In2Se3, In2S3, In2(Se1−xSx)3, (In2±yZn1±y)Se4, (In2±yZn1±y)S4 or (In2±yZn1±y)(Se1−xSx)4, where 0<x<1, 0≦y≦1 and (InxZn1−x)2+z (SeyS1−y)3+z, where 0<x≦1, 0≦y≦1 and 0≦z≦1. In one aspect,layer 302 comprises a semiconductor material which contains both In and Zn. Thesecond electrode 400 may then be deposited on the n-type semiconductor layer 302. - The solar cell is then annealed as shown in
FIG. 4B before or afterlayer 302 deposition to cause the diffusion of Zn from thelayer 303 into the p-typesemiconductor absorber layer 301. The diffusing Zn reacts with Se in the p-typeCIGS absorber layer 301 and forms an n-type semiconductor layer 305 (e.g., zinc doped CIGS) at the interface between theabsorber layer 301 and the n-type semiconductor layer 302. The annealing may be carried out at temperatures ranging from 150 to 500° C. for 20 to 1000 seconds, preferably 200 to 400 seconds, by thermal, laser or flash lamp annealing. The annealing may be carried out in theZn layer 303 sputtering chamber or in a separate chamber downstream from the Zn layer sputtering chamber. The boundary between the p-type absorber layer 301 and the n-type semiconductor layer 305 provides the pn junction for the solar cell. The depositedZn layer 303 may be entirely or partially diffused into theCIGS layer 301 by annealing to formlayer 305. For example, as shown inFIG. 4B , the entiresacrificial layer 303 is consumed. -
FIGS. 5A and 5B illustrate another embodiment of the invention. In this embodiment, as in the previous embodiments, afirst electrode 200 is deposited on asubstrate 100. Thefirst electrode 200 may comprise an optional alkalidiffusion barrier layer 201, a firsttransition metal layer 202 and a secondtransition metal layer 203. At least one p-typesemiconductor absorber layer 301 is then deposited on thefirst electrode 200. - In this embodiment, rather than depositing a
sacrificial metal layer 303 as shown inFIG. 4A , a Zn richsemiconductor buffer layer 306 is deposited on theabsorber layer 301 instead, as shown inFIG. 5A . The firstsemiconductor buffer layer 306 is a Group VI deficient (II,III)-VI semiconductor layer deposited on the p-typesemiconductor absorber layer 301. Then, a second (II,III)-VI semiconductor layer 308 is deposited on the first (II,III)-VI semiconductor layer 306. The two (II,III)-VI semiconductor layers 306, 308, have different compositions. The ratio of Group VI element to at least one of Group II or Group III elements (i.e., Group VI to metal atomic ratio) in the first (II,III)-VI semiconductor layer 306 is smaller than the ratio of the Group VI element to at least one of Group II or Group III elements in the second (II,III)-VI semiconductor layer 308. That is, the first (II,III)-VI semiconductor layer 306 has a lower concentration of Group VI element than the second (II,III)-VI semiconductor layer 308. The first (II,III)-VI semiconductor layer 306 is Group VI element poor (e.g., Zn rich) while the second (II,III)-VI semiconductor layer 308 is preferably stoichiometric. The first and second (II,III)-VI semiconductor layers 306, 308 may be deposited by any suitable method, such as by reactive sputtering described above. For example, the first (II,III)-VI semiconductor layer 306 is deposited by reactive sputtering in a sputtering atmosphere having a deficiency of Group VI element (e.g., sulfur) to form the Group VI element poor layer, while the second (II,III)-VI semiconductor layer 308 is deposited by reactive sputtering in a sputtering atmosphere having a stoichiometric ratio or excess of Group VI element. In an embodiment, the first (II,III)-VI semiconductor layer 306 comprises at least one of Zn and In and at least one of S and Se. The second (II,III)-VI semiconductor layer 308 may comprise, for example, at least one of Zn and In, and at least one of S and Se. For example, the p-typesemiconductor absorber layer 301 may comprise CIGS:Na, the first (II,III)-VI semiconductor layer 306 may comprise a sulfur poor (i.e., Zn rich) ZnS layer having a composition Zn1S1−x, where 0<x<0.3, and the second (II,III)-VI semiconductor layer 308 comprise a stoichiometric ZnS layer (e.g., Zn1S1). - The solar cell is then annealed as shown in
FIG. 5B before or after thesecond electrode 400 has been deposited on the second (II,III)-VI semiconductor layer 308. Annealing the solar cell causes diffusion of the excess Group II element, such as Zn, from the first (II,III)-VI semiconductor layer 306 into the p-typesemiconductor absorber layer 301. The diffusing Group II element reacts with the p-typesemiconductor absorber layer 301. This reaction results in the formation of an n-type II-VI semiconductor layer 307, such as a n-type ZnSe layer 307 in the top portion of the p-typeCIGS absorber layer 301, at an interface between a resulting zinc sulfide layer and p-CIGS layer 301. As noted above, if the zinc diffusion from a zincrich ZnS layer 306 into theCIGS layer 301 takes place at a relatively low temperature, such as less than about 200 C, then n-type zinc dopedCIGS layer 307 forms at the interface oflayers adjacent layers zinc selenide layer 307 between theCIGS 301 andZnS 306 layers. - The step of annealing may further cause diffusion of Na from the p-CIGS:
Na absorber layer 301 and/or from thesemiconductor layer 306 if it contains sodium into the n-ZnSe layer 307 such that the n-ZnSe layer 307 comprises ZnSe:Na. If sodium is located interstitially rather than substitutionally on zinc sites in the lattice, then Na may act as an n-type rather than p-type dopant in ZnSe. As a result of the annealing, thefirst semiconductor layer 306 may be totally consumed (i.e., completely diffused into theCIGS layer 301 and/or combined with layer 308). Alternatively, a portion of the Group IV deficientfirst semiconductor layer 306 remains on top of the formedZnSe layer 307 under the stoichiometric second (II,III)semiconductor layer 308. The resultingzinc sulfide layer 306 comprises either a stoichiometric ZnS layer if sufficient zinc diffused intolayer 307 orlayer 306 remains a sulfur poor zinc sulfide layer if the zinc to sulfur atomic ratio inlayer 306 remains greater than 1 after formation oflayer 307 by zinc diffusion fromlayer 306. After depositing the second (II,III)-VI semiconductor layer 308, thesecond electrode 400 may then deposited on the second (II,III)-VI semiconductor layer 308 before or after the annealing step. - Optionally, the reactive sputtering atmosphere may be monitored during deposition, such as with plasma emission spectroscopy, as described above. The reactive sputtering process may be controlled by providing at least one of S, Se, Zn, In, O2 or H2 into the reactive sputtering atmosphere based on the results of the monitoring during the deposition of the first and/or the second (II,III)-VI semiconductor layers 306, 308. Thus, the semiconductor layers 306 and/or 308 may optionally contain hydrogen and/or oxygen.
- It is to be understood that the present invention is not limited to the embodiment(s) and the example(s) described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims. For example, as is apparent from the claims and specification, not all method steps need be performed in the exact order illustrated or claimed, but rather in any order that allows the proper formation of the solar cells of the present invention.
Claims (25)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/334,296 US20130160831A1 (en) | 2011-12-22 | 2011-12-22 | Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/334,296 US20130160831A1 (en) | 2011-12-22 | 2011-12-22 | Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer |
Publications (1)
Publication Number | Publication Date |
---|---|
US20130160831A1 true US20130160831A1 (en) | 2013-06-27 |
Family
ID=48653365
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/334,296 Abandoned US20130160831A1 (en) | 2011-12-22 | 2011-12-22 | Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer |
Country Status (1)
Country | Link |
---|---|
US (1) | US20130160831A1 (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140041722A1 (en) * | 2012-05-17 | 2014-02-13 | Intermolecular, Inc. | Method of Fabricating High Efficiency CIGS Solar Cells |
EP2869351A3 (en) * | 2013-10-31 | 2015-07-08 | Samsung SDI Co., Ltd. | Solar cell and a manufacturing method thereof |
US20150357486A1 (en) * | 2014-06-10 | 2015-12-10 | Sk Innovation Co., Ltd. | Solar cell including multiple buffer layer formed by atomic layer deposition and method of fabricating the same |
US9786807B2 (en) | 2011-04-19 | 2017-10-10 | Empa | Thin-film photovoltaic device and fabrication method |
US9837565B2 (en) | 2012-12-21 | 2017-12-05 | Flison Ag | Fabricating thin-film optoelectronic devices with added potassium |
CN108269868A (en) * | 2018-01-29 | 2018-07-10 | 北京铂阳顶荣光伏科技有限公司 | Thin-film solar cells |
US10109761B2 (en) | 2014-05-23 | 2018-10-23 | Flisom Ag | Fabricating thin-film optoelectronic devices with modified surface |
CN110034206A (en) * | 2019-04-26 | 2019-07-19 | 潮州市亿加光电科技有限公司 | A kind of CIGS solar battery and preparation method thereof with alkali metal composite layer |
US10396218B2 (en) | 2014-09-18 | 2019-08-27 | Flisom Ag | Self-assembly pattering for fabricating thin-film devices |
US10446706B2 (en) * | 2015-05-15 | 2019-10-15 | Beijing Apollo Ding Rong Solar Technology Co., Ltd. | Hexagonal phase epitaxial cadmium sulfide on copper indium gallium selenide for a photovoltaic junction |
US10651324B2 (en) | 2016-02-11 | 2020-05-12 | Flisom Ag | Self-assembly patterning for fabricating thin-film devices |
US10658532B2 (en) | 2016-02-11 | 2020-05-19 | Flisom Ag | Fabricating thin-film optoelectronic devices with added rubidium and/or cesium |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4342879A (en) * | 1980-10-24 | 1982-08-03 | The University Of Delaware | Thin film photovoltaic device |
US4596645A (en) * | 1984-10-23 | 1986-06-24 | California Institute Of Technology | Reactively-sputtered zinc semiconductor films of high conductivity for heterojunction devices |
US7544884B2 (en) * | 2002-09-30 | 2009-06-09 | Miasole | Manufacturing method for large-scale production of thin-film solar cells |
US20100154885A1 (en) * | 2008-12-19 | 2010-06-24 | Yang Chien-Pang | Thin film solar cell and manufacturing method thereof |
US20100258191A1 (en) * | 2009-04-13 | 2010-10-14 | Miasole | Method and apparatus for controllable sodium delivery for thin film photovoltaic materials |
US20110162705A1 (en) * | 2010-01-06 | 2011-07-07 | Popa Paul J | Moisture resistant photovoltaic devices with elastomeric, polysiloxane protection layer |
-
2011
- 2011-12-22 US US13/334,296 patent/US20130160831A1/en not_active Abandoned
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4342879A (en) * | 1980-10-24 | 1982-08-03 | The University Of Delaware | Thin film photovoltaic device |
US4596645A (en) * | 1984-10-23 | 1986-06-24 | California Institute Of Technology | Reactively-sputtered zinc semiconductor films of high conductivity for heterojunction devices |
US7544884B2 (en) * | 2002-09-30 | 2009-06-09 | Miasole | Manufacturing method for large-scale production of thin-film solar cells |
US20100154885A1 (en) * | 2008-12-19 | 2010-06-24 | Yang Chien-Pang | Thin film solar cell and manufacturing method thereof |
US20100258191A1 (en) * | 2009-04-13 | 2010-10-14 | Miasole | Method and apparatus for controllable sodium delivery for thin film photovoltaic materials |
US20110162705A1 (en) * | 2010-01-06 | 2011-07-07 | Popa Paul J | Moisture resistant photovoltaic devices with elastomeric, polysiloxane protection layer |
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9786807B2 (en) | 2011-04-19 | 2017-10-10 | Empa | Thin-film photovoltaic device and fabrication method |
US20140041722A1 (en) * | 2012-05-17 | 2014-02-13 | Intermolecular, Inc. | Method of Fabricating High Efficiency CIGS Solar Cells |
US10153387B2 (en) | 2012-12-21 | 2018-12-11 | Flisom Ag | Fabricating thin-film optoelectronic devices with added potassium |
US9837565B2 (en) | 2012-12-21 | 2017-12-05 | Flison Ag | Fabricating thin-film optoelectronic devices with added potassium |
EP2869351A3 (en) * | 2013-10-31 | 2015-07-08 | Samsung SDI Co., Ltd. | Solar cell and a manufacturing method thereof |
US10431709B2 (en) | 2014-05-23 | 2019-10-01 | Flisom Ag | Fabricating thin-film optoelectronic devices with modified surface |
US10109761B2 (en) | 2014-05-23 | 2018-10-23 | Flisom Ag | Fabricating thin-film optoelectronic devices with modified surface |
US10672941B2 (en) | 2014-05-23 | 2020-06-02 | Flisom Ag | Fabricating thin-film optoelectronic devices with modified surface |
TWI684288B (en) * | 2014-06-10 | 2020-02-01 | 南韓商Sk新技術股份有限公司 | Solar cell including multiple buffer layer formed by atomic layer deposition and method of fabricating the same |
US20150357486A1 (en) * | 2014-06-10 | 2015-12-10 | Sk Innovation Co., Ltd. | Solar cell including multiple buffer layer formed by atomic layer deposition and method of fabricating the same |
CN105206690A (en) * | 2014-06-10 | 2015-12-30 | Sk新技术株式会社 | Solar cell including multiple buffer layer formed by atomic layer deposition and method of fabricating the same |
US10396218B2 (en) | 2014-09-18 | 2019-08-27 | Flisom Ag | Self-assembly pattering for fabricating thin-film devices |
US10446706B2 (en) * | 2015-05-15 | 2019-10-15 | Beijing Apollo Ding Rong Solar Technology Co., Ltd. | Hexagonal phase epitaxial cadmium sulfide on copper indium gallium selenide for a photovoltaic junction |
US10658532B2 (en) | 2016-02-11 | 2020-05-19 | Flisom Ag | Fabricating thin-film optoelectronic devices with added rubidium and/or cesium |
US10651324B2 (en) | 2016-02-11 | 2020-05-12 | Flisom Ag | Self-assembly patterning for fabricating thin-film devices |
US10971640B2 (en) | 2016-02-11 | 2021-04-06 | Flisom Ag | Self-assembly patterning for fabricating thin-film devices |
US11257966B2 (en) | 2016-02-11 | 2022-02-22 | Flisom Ag | Fabricating thin-film optoelectronic devices with added rubidium and/or cesium |
CN108269868A (en) * | 2018-01-29 | 2018-07-10 | 北京铂阳顶荣光伏科技有限公司 | Thin-film solar cells |
CN110034206A (en) * | 2019-04-26 | 2019-07-19 | 潮州市亿加光电科技有限公司 | A kind of CIGS solar battery and preparation method thereof with alkali metal composite layer |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8313976B2 (en) | Method and apparatus for controllable sodium delivery for thin film photovoltaic materials | |
US7897020B2 (en) | Method for alkali doping of thin film photovoltaic materials | |
US20130160831A1 (en) | Reactive Sputtering of ZnS(O,H) and InS(O,H) for Use as a Buffer Layer | |
US7785921B1 (en) | Barrier for doped molybdenum targets | |
US8115095B2 (en) | Protective layer for large-scale production of thin-film solar cells | |
US7935558B1 (en) | Sodium salt containing CIG targets, methods of making and methods of use thereof | |
US8110738B2 (en) | Protective layer for large-scale production of thin-film solar cells | |
US20100236628A1 (en) | Composition and method of forming an insulating layer in a photovoltaic device | |
US20120031492A1 (en) | Gallium-Containing Transition Metal Thin Film for CIGS Nucleation | |
US20110162696A1 (en) | Photovoltaic materials with controllable zinc and sodium content and method of making thereof | |
US8048707B1 (en) | Sulfur salt containing CIG targets, methods of making and methods of use thereof | |
US10211351B2 (en) | Photovoltaic cell with high efficiency CIGS absorber layer with low minority carrier lifetime and method of making thereof | |
EP2399295A2 (en) | Protective layer for large-scale production of thin-film solar cells | |
US20120090671A1 (en) | Modified band gap window layer for a cigs absorber containing photovoltaic cell and method of making thereof | |
US9284639B2 (en) | Method for alkali doping of thin film photovoltaic materials | |
US9169548B1 (en) | Photovoltaic cell with copper poor CIGS absorber layer and method of making thereof | |
US20130000702A1 (en) | Photovoltaic device with resistive cigs layer at the back contact |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MIASOLE, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ZUBECK, ROBERT;DORN, RANDY;REEL/FRAME:027510/0008 Effective date: 20111221 |
|
AS | Assignment |
Owner name: PINNACLE VENTURES, L.L.C., CALIFORNIA Free format text: SECURITY AGREEMENT;ASSIGNOR:MIASOLE;REEL/FRAME:028863/0887 Effective date: 20120828 |
|
AS | Assignment |
Owner name: MIASOLE, CALIFORNIA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:PINNACLE VENTURES, L.L.C.;REEL/FRAME:029579/0494 Effective date: 20130107 |
|
AS | Assignment |
Owner name: HANERGY HOLDING GROUP LTD., CHINA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MIASOLE;REEL/FRAME:032092/0694 Effective date: 20140109 |
|
AS | Assignment |
Owner name: APOLLO PRECISION FUJIAN LIMITED, CHINA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HANERGY HOLDING GROUP LTD.;REEL/FRAME:034826/0132 Effective date: 20141125 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: BEIJING APOLLO DING RONG SOLAR TECHNOLOGY CO., LTD Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:APOLLO PRECISION FUJIAN LIMITED;REEL/FRAME:037855/0478 Effective date: 20160225 |